Development of reasoning about random events.

Abstract

The development of school students' understanding of random events is explored in three related studies based on tasks well known in the research literature. In Study 1,99 students in Grades 3 to 9 were interviewed on three tasks and surveyed on two tasks about luck and random behaviors in chance settings. Four levels of response are identified across the five tasks, reflecting increasing structural complexity and statistical appropriateness. In Study 2,23 of these students were interviewed on the same interview protocol tasks, three or four years later to monitor developmental change. In Study 3, a different group of 15 students was interviewed with two of the tasks and prompted with conflicting responses of other students on video. The aim of Study 3 was to monitor the influence of cognitive conflict in improving student levels of response. Implications for teachers, educational planners, and researchers are discussed in the light of other researchers' findings.

Introduction

Many research studies over the years have explored people's understanding of random processes. The original studies mainly dealt with college students and their misunderstandings by describing from a psychological perspective how people reason in uncertain conditions, a psychological approach. Later studies were conducted by mathematics educators on data sets composed of school students, some showing little change in understanding across grades. The desire to improve students' statistical understanding and reasoning motivated this research, an educational approach. These two different research perspectives and the contributions they make to the literature on probability and statistics have been considered in some detail by Shaughnessy (1983, 1992). After a review of the place of the random concept in the school curriculum and of previous research on the concept, this study uses familiar tasks to extend previous research in three directions. First, a development model is proposed that displays increasingly complex understandings of the concept of random as involved in the tasks presented. Second, longitudinal interview data are used to monitor the developmental change in understanding over three or four years. Third, cognitive conflict from other students is introduced as a means of testing the tenacity of beliefs and their susceptibility to change. Background for these three avenues of research is also provided.

Random in the School Curriculum

As a key probability concept, random is notoriously difficult for students to grasp. Used as an adjective, more attention is often given to the associated noun, such as in "random sample," to give meaning to a complex idea (Batanero, Green, & Serrano, 1998). The word is often used colloquially in non-mathematical contexts to convey a meaning of haphazard. This is reflected to some extent in the nebulous nature of some dictionary definitions, for example, "Made, done without method or conscious choice" (Waite, 1998, p. 530). Indeed like many concepts that are difficult to define, it seems easier to define random by considering "antonyms to randomness" and exploring what is not random, for example, "order," "organization," and "predictability" (Falk, 1991). Curriculum documents are generally guilty of discussing random events, and random numbers, without specifically defining the term "random" (e.g., Australian Education Council [AEC], 1991; Department for Education, 1995; Ministry of Education, 1992; National Council of Teachers of Mathematics [NCTM], 2000). An exception is the Mathematics Guidelines K-8: Overview to Chance and Data of the Department of Education and the Arts [DEA] in the Australian state of Tasmania, which follows closely the model provided by Moore (1990).

The focus on chance in this Strand is to develop in students the ability
to describe randomness and to measure (quantify) uncertainty. Phenomena
or events which may individually have uncertain outcomes (for example,
tossing a coin), but that have a regular pattern of outcomes over the
long term, are referred to as being random. (For example, we would
expect that in tossing a coin, over the long term, approximately 50%
will be heads). Teachers should provide a range of activities for
students to help them to start to develop, in mathematical terms, an
understanding of the difference between random and what we might
describe in every day language as haphazard (DEA, 1993, p.6).

The implications of the concept of random for the curriculum are well stated, however, by the NCTM (2000). If an event is random and if it is repeated many, many times, then the distribution of outcomes forms a pattern. The idea that individual events are not predictable in such a situation but that a pattern of outcomes can be predicted is an important concept that serves as a foundation for the study of inferential statistics (p. 51).

Luck, as a word often associated colloquially with chance, attracts very
little attention in curriculum documents. In its earliest band of
experiences for chance, the AEC (1991) suggests, "Use with clarity,
everyday language associated with chance events" (p. 166) and as a
possible activity, "Clarify and use common expressions such as 'being
lucky'" (p. 166). As is shown by a dictionary definition, however,
colloquial connotations can make interpreting comments and reasoning by
students difficult: "Good or bad fortune; circumstances brought by this;
success due to chance" (Waite, 1998, p. 378).

Many applaud the fact that in recent years school curricula around the world have introduced random phenomena to students, but there is also concern about providing for appropriate statistical understanding (Batanero et al., 1998). Research over the years has shown that people do not appear to develop these intuitions naturally.

Previous Research on Random Phenomena

The research on random concepts began with the work of psychologists, using students at the college level and focusing on misconceptions (Kahneman & Tversky, 1972, 1973, 1982). Relevant to the current study was their account of the representativeness heuristic, which reflects how well the outcome of an event (or sample) reflects the parent population. Misconceptions related to representativeness are often based on putting too much confidence in small samples, for example, in expecting the same exact proportion in samples as in the population, in expecting frequent oscillation in random outcomes, and in expecting current outcomes to balance those obtained previously. It was a few years before research began to focus on school students' appreciation of the nature of random behavior. Fischbein and Gazit (1984) considered middle school students' intuitions from the same perspective as the earlier psychologists, whereas Green (1983) took a more mathematical approach, also considering problems of probability based on proportional reasoning.

In terms of the tasks employed by the current study, the one reported most frequently in the literature is based on the sequential birth order of six babies in a hospital, assuming boys (B) and girls (G) are equally likely to be born and the process is random. Kahneman and Tversky (1972) found with college students that 82% judged the sequence BGBBBB to be less likely to occur than GBGBBG. Likewise, BBBGGG was deemed significantly less likely to occur than the sequence GBBGBG. Shaughnessy (1977) reported that 62.5% of his college sample responded in a similar fashion, even when the option of "same chance" was included. Garfield and delMas (1991) employed the same two pairs of sequences for comparison, again including the opportunity for students to choose "equally likely." In exploring both the "exact proportion" belief (BGGBGB versus BBBBGB) and the "random order" belief (BGGBGB versus BBBGGG), 47% of their pre-test college sample held both misconceptions with a further 32% choosing correctly for one pair, and 21% choosing the correct response for both sets. Konold, Pollatsek, Well, Lohmeier, and Lipson (1993) adapted the question for a coin tossing scenario and also asked their college sample which of a group of outcomes was least, as well as most, likely to occur. Initially their findings were contrary to many earlier results in that overall, 72% correctly chose the option "equally likely" when asked to indicate which sequence was most likely to occur; reasoning based on the representative heuristic was limited. When asked which sequence was least likely to occur, however, only 38% chose the "equally likely" option. Reasoning was not consistent and beliefs were not stable, with similar differences and inconsistencies found in follow-up interviews with the same question.

Fischbein and Gazit (1984) exploited the lottery scenario to explore school students' understanding of random processes. In a questionnaire given to students in Grades 5, 6, and 7 they considered the idea of winning numbers being "lucky," within the context of the lottery. Few students agreed to the idea of luck influencing the outcome and an increasing number of students over the grades correctly rejected luck. There were, however, high response levels for the belief that "the same number cannot win anymore," a common misconception. In the same study they used a task comparing the likelihood of a consecutive sequence of numbers versus a "random" sequence of numbers in winning a lottery. The authors reported the persistence of the belief that it is more probable that random numbers would win in a lottery draw, with the percentage of students' responses in Grade 6 and 7 averaging 45%. In a follow-up study with students from Grade 5 to college, Fischbein and Schnarch (1997) found performance improved with increasing grade on the consecutive-number lottery question with reasoning moving away from a representative belief. Watson, Collis, and Moritz (1995) also observed improved performance over Grades 3, 6, and 9 for the task exploring the belief in lucky numbers.

Very little has been reported in the literature about students' descriptions of the word "random" or random processes. Moritz, Watson, and Pereira-Mendoza (1996) asked students, "What things happen in a random way?" and found increasing sophistication in responses with grade. A range of phenomena related to humanly constructed processes such as breath tests, to natural events such as earthquakes, and to games such as a lottery, was suggested as things that happen in a random way. Some responses included characteristics of a random process such as "things that happen in no pattern or order" or "you choose jelly beans from a packet and don't know which one you'll get--nothing influences your choice." Non-response also declined, in that 78% of Grade 3 did not respond to the question but only 16% of Grade 9 did not respond. Watson, Kelly, Callingham, and Shaughnessy (2003) augmented the above question by asking what the word "random" means. Achieving the highest level response was one of the most difficult tasks in a survey assessing understanding of chance, data, and variation.

Developmental Research into Students' Understanding of Random Events

Although there has been more research into students' probabilistic understanding than into understanding of other parts of the chance and data curriculum (e.g., Green, 1983; Fischbein & Gazit, 1984; Fischbein & Schnarch, 1997), much of this has focused on identifying misconceptions rather than documenting the development of understanding with respect to the increased complexity and appropriateness of responses. Watson et al. (1995) and Watson, Collis, and Moritz (1997) considered students responses to tasks related to luck and to chance measurement using a structural model from cognitive psychology (Biggs & Collis, 1982, 1991). They found it possible to identify cycles of responses reflecting the number of elements of a task used in a response and how these elements were combined. At the prestructural or ikonic level (IK) reasoning was imaginative not reflecting the relevant elements of the tasks. At the unistructional level (U), responses employed a single relevant element of the task and if conflict occurred for elements, this was not recognized. At the multistructural level (M) responses used more than one element, usually in sequence, and if conflict arose it was recognized but not completely resolved. At the relational level (R), responses tied together relevant elements of the task for closure, resolving conflict if it occurred. For one item involving proportional reasoning, Watson et al. (1997) identified a second UMR cycle associated with correct reasoning to support an answer.

This identification of increasingly complex levels of development of ideas was similar to that employed in analyzing responses to tasks related to average (Watson & Moritz, 1999a), to sampling (Watson & Moritz, 2000a), to comparing data sets (Watson & Moritz, 1999b), and to creating pictographs (Watson & Moritz, 2001b).

Longitudinal Research on Student Understanding

Until recently there has been very little longitudinal research in relation to the chance and data school curriculum. In 1988, Garfield and Ahlgren called for "longitudinal studies of how individuals actually develop in stochastic sophistication" (p. 58) and this was reinforced periodically thereafter (Green, 1993; Shaughnessy, 1997). Green (1991) conducted a follow-up study of 305 students, four years after they had been surveyed on questions related to "randomness" and "comparison of odds" (Green, 1988). Over the four years there was very little change in the prediction of random outcomes in a two-dimensional grid but the development in "comparison of odds" was quite marked over the time period. Green considered that a lack of curriculum exposure to the behavior of random generators possibly contributed to the difference in performance on the two questions.

In follow-up to initial developmental analyses of chance measurement tasks for school students (Watson et al., 1997), Watson and Moritz (1998) considered longitudinal data collected after two and four years. Overall they observed an average increase of one developmental level over four years. In a related area of the chance curriculum, Watson and Moritz (2002) found that performance on conditional and conjunction probability tasks did not change markedly over two or four years. This may have been due to a lack of emphasis on these ideas in the curriculum. In extending research methodologies to follow the change of students' statistical concepts over time, a number of studies that are part of the larger project which includes the current study, have employed the use of interviews, including work on average (Watson & Moritz, 2000b), representing, interpreting, and predicting with pictographs (Watson & Moritz, 2001b), inferential reasoning and observation of variation in graphical presentations (Watson, 2001), sampling (Watson, 2004), and fairness of dice (Watson & Moritz, 2003).

Research Involving Cognitive Conflict

For educational researchers, exploring the irregularities and conflicts that arise in the understanding of students enriches the process of facilitating conceptual development. In learning, cognitive conflict arises during the process of conceptual change whereby a student becomes aware that an existing concept or belief does not adequately explain a new experience or idea (Strike & Posner, 1992). Within a classroom, students may naturally experience a sense of "dissatisfaction" through their own reading and investigation, or be exposed to new ideas through the intervention of their teachers and other students. This conflict may cause students to reevaluate and adjust a concept or, in reconsidering an idea, reject a conflicting idea and strengthen an existing concept. Macbeth (2000) outlines four types of "teaching moves" that facilitate conceptual change: (a) providing opportunities for pupils to make their own conceptions about a particular topic area explicit so that they are available for inspection, (b) presenting empirical counterexamples, (c) presenting and reviewing alternative conceptions, and (d) providing opportunities to use conceptions. The challenge for researchers is to simulate appropriate environments and integrate these teaching concepts into their investigations. This is not easy and can be confounded in a number of ways, particularly with research involving collaborative group-work (Chick & Watson, 2001).

Cognitive conflict is often suggested as a strategy in relation to the
development of appropriate curriculum guidelines and teaching approaches
for science education (Macbeth, 2000; Posner, Strike, Hewson, & Gertzog,
1982). Such a move is largely influenced by the desire for scientific
theories to be aligned with everyday intuitions. In a sense, the
mathematics curriculum experiences the same dilemma as science,
particularly in the area of probability, in that "the gap between
potential everyday applicability and formal understanding is at its
greatest" (Pratt, 1998, p. 2).

In the larger project of which this study was a part, cognitive conflict was utilized in an individual interview environment, where videotaped responses from students interviewed earlier were used to present cognitive conflict to those currently being interviewed. For a task on chance measurement, 33% of students responded at higher levels in the presence of cognitive conflict (Watson & Moritz, 2001a). For tasks on sampling the improvement rate was 22% (Watson, 2002a). For easier tasks on comparing two data sets of equal size (Watson, 2002b) and creating pictographs (Watson & Moritz, 2001b), cognitive conflict assisted about 60% of students, whereas for more difficult tasks with unequal sized groups or predicting from pictographs, improvement rates dropped to about 30%.

Research Questions

In three closely related studies the following research questions are addressed for students' understanding of random processes.

1. What are the observed cognitive levels of performance for random tasks? Do these vary with grade? What is the degree of association of levels of response among tasks?

2. How does students' reasoning develop over time? Do levels of response improve over 3 or 4 years?

3. Can other students' ideas be used to prompt cognitive conflict and improve response levels?

Methodology

Participants

A total of 99 Australian school students were included in this research as part of a wider research project. Students were from seven Tasmanian government schools, including three primary, two district, and two secondary, and a private school in South Australia. Table 1 shows the demographic data for participants in each of the studies described below.

In Study 1, 84 Tasmanian students were surveyed and interviewed: twenty-four students from Grade 3 (aged 8-9), thirty students from Grade 6 (aged 11-12), and thirty students from Grade 9 (aged 14-15). Fifteen South Australian students were also interviewed; three students from Grade 3 (aged 8-9), seven students from Grades 5 and 7 (aged 10-11 and 12-13 respectively), and four students from Grade 9 (aged 14-15). The researchers selected students for interview based on their responses to survey items. Students were judged either as being representative of their grade level or as providing unusual answers to some questions, although not necessarily the questions discussed here. These students were also regarded by their teachers as articulate and prepared to discuss their ideas with an interviewer. Not all participants answered all five items and hence reduced sample sizes will be reported as appropriate.

Follow-up interviews were conducted three or four years later with 23 students from Study 1. Five Grade 3 students (aged 8-9), fourteen Grade 6 students (aged 11-12), and four Grade 9 students (aged 14-15) completed a second, longitudinal, interview.

In Study 3, a different group of 15 Tasmanian students from government schools participated in interviews involving cognitive conflict. The students were a Grade 3 student (aged 8-9), seven Grade 6 students (aged 11-12), and seven Grade 9 students (aged 14-15). Their initial interview responses, before being presented with cognitive conflict, were included with the data in Study 1.

Tasks

The Random Protocol used in this study consisted of two survey questions and three interview questions (Figure 1). These items were parts of two instruments developed to assess student understanding of statistical concepts. The items were among a larger set chosen to meet five practical criteria: 1) to reflect the current national curriculum guidelines, 2) to take into account the existing research from other countries, 3) to allow for different levels and modes of cognitive functioning, 4) to be motivating and elicit optimal responses, and 5) to be practical to administer and interpret (Watson, 1994).

Both survey questions were adapted from Fischbein and Gazit (1984). Question QS1 explored random processes and was related to the "chance language" aspect of the curriculum. Question QS2, investigated students' understanding of luck, particularly in relation to the curriculum reference related to "interpreting events."

Questions QI1 on the interview protocol provided an opportunity for students to show their understanding of what "random" means and to show if they appreciated random elements embedded in a context. Question QI2 was adapted from Fischbein and Gazit (1984) to study the appreciation of random as a chance process within the familiar social context of the lottery. Question QI3, based on an item of Garfield and delMas (1991), explored students' conceptions of order and equal-likelihood in a context where representativeness is also an issue in an observed sequential sample. The interview protocol in Study 2 was identical to that used in Study 1.

The cognitive conflict interview protocol that was used in Study 3 extended QI2 lottery and QI3 birth order tasks (see Figure 1) to include the responses of other students. After their initial responses, students were prompted with video footage of responses from other students in earlier interviews. Prompts were selected by the interviewer as different from the participant's response in order to create cognitive conflict. Prompts available for use with QI2 are shown in Figure 2 and those for QI3 in Figure 3. After being asked to comment on the prompt, students were asked to decide the better or best response. It was anticipated that this procedure, based on input from other students rather than teachers or researchers, would simulate a comparable learning environment in the classroom.

[FIGURE 1 OMITTED]

Procedure

Surveys were administered during school class time with 45 minutes allocated to complete the whole survey. In the secondary schools they were distributed during a mathematics class. For primary classes in particular, teachers assisted students in reading the questions, but did not provide explanations or answers. It was explained to the younger students that they might find some questions easy and some harder as the questions were for older students as well.

[FIGURE 2 OMITTED]

The interviews were also conducted during class time with all sessions videotaped. Students participated in a 45-minute individual interview in the course of which several protocols related to the chance and data part of the mathematics curricula were administered. The Random Protocol formed one part of the interview; other topics included interpreting bar charts, comparing graphs, average, sampling, fairness of dice, and probability. The Random Protocol was presented toward the end of the interview session and hence was sometimes cut short or omitted due to time constraints.

Coding and Analysis

Both authors coded the two survey questions and the three interview questions. A spreadsheet system that linked the digitized interview videos, the transcripts, and survey responses facilitated this process. For Study 1, all students' responses for each item were coded in two stages; initially, similar types of responses were grouped together in a clustering technique and assigned a code (Miles & Huberman, 1994); these codes were then assigned to one of four levels--Ikonic (IK), Unistructural (U), Multistructural (M), Relational (R)--within the cognitive framework of Biggs and Collis (1982, 1991). Each level from the ikonic to relational represents an increase in the complexity of structure and appropriateness of responses. The coding framework allowed for continuity across the questions in that a similar structural complexity and statistical appropriateness related to the concept of random could be identified for each item. The longitudinal responses in Study 2 were also coded using this framework. Changes in students' response levels hence could be tracked for each item. For Study 3, codes were applied to the prompts; final responses coded within the above framework could then be associated with the level of the prompt.

[FIGURE 3 OMITTED]

Missing data for some students meant that comparison of total scores across tasks for students was not a meaningful process. Response levels are presented for different grades for questions where appropriate, as are indicative mean values. The association of levels of response among the questions was considered using two-way tables. The Pearson product-moment correlation coefficient was used as an indicator of the strength of association. Change over time and after the presentation of cognitive conflict is considered descriptively. The results are presented in the order of the research questions.

Results

Research Question 1: Development of Understanding

Although the levels of response for coding the five questions were consistent, the distribution of levels of response varied greatly among the questions. For this reason descriptive accounts will be given for the five questions separately and the association of levels of response between pairs of items will be considered. Table 2 contains an overall description of the levels of response, with highlights of features observed on the individual questions, combining survey and interview questions on "the meaning of random." The codes reflect the observed levels of development of Biggs and Collis (1982, 1991) as detailed earlier.

Random survey question QS1. The survey question "What things happen in a random way?" was answered by 71 students and its reference to "things" encouraged the presentation of examples rather than responses of a definitional nature. Some students, however, did provide a broad description, in what might be called an optimal rather than functional response. For this question all Level 0 responses were in fact non-responses on the survey sheet. At Level 1 responses reflected intuitive ideas or personal experiences that were likely to be based in idiosyncratic contexts, for example, "work sheets," "puzzling things," "a car will crash," or "trees grow." Level 2 responses were generally single recognizable examples, such as "the weather," "Tattslotto numbers," and "when you get picked out of a number of people," or a single characteristic of a random process, such as "by chance" and "any order, higgledy, piggledy." At Level 3, responses went further in describing the process combining a description and an example, or providing examples of different types of random processes.

S1: The rolling of a dice, when rain comes from the sky, what the weather is like. [Grade 9]

S2: Something that isn't organized, there is no particular pattern to what is happening. [Grade 9]

S3: The Tattslotto numbers come up randomly; each number has an equally small chance of getting chosen. [Grade 9]

No responses reached Level 4 sophistication on the survey question.

Table 3 shows the distribution of levels of response across the grades for question QS1. The association of coding level with grade shows improving performance overall with grade, the average level of Grade 3 being .68, with 1.41 for Grade 6, and 1.95 for Grade 9.

Random interview question, QI1. The interview question on the meaning of random, QI1, offered more support than the survey question, principally by providing a context, a television announcement about a lottery, for eliciting students' ideas. Coding was assigned for Part (a) and Part (b) of this question; these codes were then combined to a single code. At Level 0, only one response was recorded where the student did not respond to either part. Many of the Level 1 responses, however, had no initial suggestion for the first part but within a context could provide an intuitive response or elaborate on the process taking place in the drawing of lottery numbers in the second part.

S4: [a] No response. [b] They just come out, all kinds. [Grade 3]

S5: [a] Just grab a few people, random people just go around the school ... they just grab them. [b] The machine just picks out the numbers and they come up and you get more numbers come up than others I have seen. [Grade 9]

Level 2 responses again reflected single ideas or examples, which could be given for either or both parts of the question.

S6: [a] It means you sort of guess. [b] They are not picking them themselves, they are just letting them come up. [Grade 6]

S7: [a] You might say random as in randomly pick. It is just a lucky one, a lucky pick. [b] They haven't done anything with the camera or anything to make it show a certain number. They would just pick them out and that is their lucky pick. [Grade 6]

Level 3 responses combined multiple ideas and examples.

S8: [a] Choosing at random like in raffles, and they say "pick a name out of a hat," and then it could be any. [b] They just pick some out and they could be any of them. No really definite numbers and so it could be any so you have just as much chance of them being yours. [Grade 6]

S9: [a] When you pick names or numbers out of a hat, everyone has got an equal chance. [Grade 9]

At Level 4 responses included comments about avoiding bias in the selection process.

S10: [a] Well random is used a lot ... like in elections when they do popularity polls ... or they take random phone numbers out of the book. It is a way of selecting a sample, without trying, not to be biased so it can fairly fair. Like feed the names into the computer and they select a few names out of whatever. [b] It means there's any possibility of any numbers coming up, they are saying that to make it sound like they don't cheat or rig it. [Grade 9]

Table 4 shows the distribution of levels of response across the grades for question QI1 for the 99 students who were interviewed. Again there was an association of performance with grade indicated by increasing average codes from 1.69 for Grade 3, to 2.32 for Grade 6, and 2.94 for Grade 9. These averages are approximately one level higher than obtained for the same grades on the survey question QS1. The value of the interview in reducing the number of non-responses is seen. The association of responses for the levels of response of the two questions is fairly strong as is shown in Table 5 (r = .592, p < .0005). Only two students responded at a lower level in the interview than on the survey, with 93% of non-responses and 68% of Level 1 and Level 2 responses improving from the survey to the interview.

Lucky numbers survey question, QS2. The survey question, QS2, about Claire's belief in lucky numbers, was answered by 84 students. Level 0 responses were non-responses, or "yes" or "no" responses with no accompanying explanation, whereas Level 1 responses reflected a belief in "luck."

S11: The same numbers always win. [Grade 3]

S12: She CHOSE lucky numbers. [Grade 3]

Level 2 responses stated disagreement with Claire's view either implicitly or explicitly, or expressed an "anything can happen" view of the context.

S13: I wouldn't do it. [Grade 3]

S14: They wont [sic] win it for her again. [Grade 3]

S15: It's a superstition. [Grade 6]

S16: In Tattslotto not often the numbers are the same so I think it's impossible. [Grade 6]

S17: It does not matter what numbers you have you might win. [Grade 3]

Some responses went on to express a qualitative chance statement in support of the view disagreeing with Claire at Level 3.

S18: No number has more chance of being drawn than any other. [Grade 9]

S19: Because Tattslotto is random it makes no difference. It may come out SOMETIMES but randomly. But if you have the same numbers at least you wouldn't get frustrated because you didn't put in the same numbers as last week. [Grade 6]

No responses were observed at a level higher than Level 3.

As can be seen in Table 6, the predominant response for QS2 for all grades was Level 2 disagreement with Claire's belief but with little in the way of justification. There was again a slight trend for improvement in levels of response with grade, with more Level 3 responses provided at Grade 9. Average code levels for the three grades were 1.46, 2.03, and 2.33, respectively.

Lottery interview question, Q12. Interview question, QI2, on choosing sequential or "spread out" numbers for a lottery was answered by 98 students. Only two responses provided idiosyncratic reasoning at Level 0.

S11: [Writes down 13, 22, 39, 7, 15, 43. Chooses Jenny] My Tattslotto number's 7 and it comes up every night so I think the first one. [Grade 3]

S7: [Chooses Jenny] I wouldn't send that one [Ruth] because it is cheating. [Grade 6]

At Level 1, however, many responses expressed straightforward disagreement with Ruth's numbers and favored Jenny's numbers, with justification based on the observation that numbers are generally more "spread out" and "mixed up."

S20: [Writes down 10, 35, 7, 29,40, 39. Chooses Jenny] It is not very usual for all the numbers that are picked are in a row, because they are not usually in a row, they are spread out. [Grade 6]

S21: [Writes down, 42,3,45,21, 10, 9. Chooses Jenny] The balls never really go 1, 2, 3, 4, 5, 6. There's more chance of random numbers. [Grade 6]

S22: [Writes down 7, 23, 11, 39, 41, 9. Chooses Jenny] It has a better range of numbers in it. [Grade 3]

At Level 2 responses were likely to express contradictory ideas without realization.

S23: [Writes down 10, 11, 12, 13, 14, 15. Chooses Equally Likely] Equally but I don't think, you never really have small numbers, mostly they're big numbers. [Grade 6]

S24: [Writes down 24, 43, 3, 17, 39, 33. Chooses Jenny] Have the same chance but it is unlikely, it has never happened 1, 2, 3, 4, 5, 6, they always come up randomly. [Grade 6]

At Level 3 students chose "equally likely" for the chance of Ruth's and Jenny's numbers being drawn in the lottery, with qualitative chance justifications.

S25: [Choose Equally Likely] 50/50 chance. If they are both in, there is an equal chance of both of them winning, the machine could pick any of them. [Grade 6]

S26: [Writes down 7,9,32,40,22,14. Chooses Equally Likely] It's unlikely that you would get consecutive numbers but either has just as much chance because they are just picking any numbers randomly out of the thing. [Grade 9]

Responses at Level 4 focused explicitly on each number having the same chance of being chosen and /or included mention of bias.

S27: [Writes down 7, 13, 26, 36, 39, 17. Chooses Equally Likely] I think they have the same chance because they all have the same chance, like a 1 in 45 chance of coming up. [Grade 9]

S28: [Writes down 1, 5, 36, 12, 10, 18. Chooses Equally Likely] Either one has got an equal chance. The Tattslotto thing isn't biased, there's the same chance of getting every number. So just as likely to get consecutive numbers than different numbers. [Grade 9]

Table 7 shows that responses reflecting the view that the choice of numbers with spread was more likely to win were the most common at all grade levels. There was, however, a trend for higher average codes with grade from 1.12 in Grade 3, to 1.74 in Grade 6, and 2.32 in Grade 9. Although there was a predominance of Level 1 responses to this question and Level 2 responses to the survey question on lucky lottery numbers, it is interesting to observe the association of the two sets of responses for the 84 students who answered both (r = .438, p<.0005). This is shown in Table 8 where 46% of all students responded with disagreement on the existence of lucky numbers but agreement with a "spread out" choice of numbers as more likely than a sequence.

The association of levels of responses for the two interview questions on the meaning of random, QI1, and the lottery question, QI2, is shown in Table 9. For the 91 students with data for both questions, there is a tendency for an association for those with codes of 2 or higher on the lottery question; for those at Level 1 on QI2, however, there is a wide spread and a fairly even representation of responses at Level 1 and Level 3 to the random definition question QI1 (r = .481, p < .0005). It would appear that belief in the necessity for lottery numbers to be "spread out" to increase the chance of winning is held by students with a wide range of ability to explain the meaning of random more generally.

Birth order interview question, QI3. The interview question, Q13, on the birth order for six babies was answered by 83 students. The levels of response were determined both by choices between the possible birth sequences and by the reasoning associated with the pair of choices. Level 0 responses made choices but gave no supporting reasons or explanations. At Level 1, most responses chose BGGBGB consistently and displayed both beliefs, that there should not be an imbalance of gender and that there should not be straight runs of boys followed by girls.

S4: [Chooses BGGBGB Part (a)] There's 3 of each. [Chooses BGGBGB Part (b)] You wouldn't have 3 boys and then 3 girls born. [Grade 3]

One response, however, selected BBBGGG for the second pair.

S29: [Chooses BGGBGB Part (a)] You've got a variety of children being born and they're not always girls and not always boys. [Chooses BBBGGG Part (b)] It's a different type but there might be all boys coming and then all girls. [Grade 6]

At Level 2 responses chose "equally likely" for each part but gave no supporting reasons besides an "anything can happen" justification.

S30: [Chooses Equally Likely for both parts] Because you don't know which is going to come out a boy or a girl. [Grade 3]

S23: [Chooses Equally Likely for both parts] Because it just depends which baby they have, it could be any really. [Grade 6]

At Level 3, responses recognized that one of the apparent imbalances (number of boys and girls or order of birth) did not affect the overall chances but were susceptible to the other; that is in one part a sequence of births was specified as being "more likely" whereas the other part was answered "equally likely" with appropriate reasoning.

S31: [Chooses BGGBGB Part (a)] Boys and girls are evenly matched. [Chooses Equally Likely Part (b)] They have both got 3 again. [Grade 9]

S32: [Chooses Equally Likely Part (a)] It can be that many boys with 1 girl or it could be equally the same. [Chooses BGGBGB Part (b)] More likely because it's a mixture. [Grade 9]

For the highest level of response, students were not susceptible to either type of apparent imbalance and gave appropriate justifications for their choices in both cases.

S8: [Chooses Equally Likely for both parts] Because it has as much chance as being a boy and a girl, so it could be in any order at all. [Grade 6]

Table 10 shows the distribution of levels of response across grades for the birth order problem, QI3. More improvement occurs between Grades 3 and 6 in average level of performance (1.55 to 2.14) than between Grades 6 and 9 (2.14 to 2.38). In terms of association of level of response with the other two interview questions, data are given in Tables 11 and 12. There is no relationship between the levels of response for birth order and random tasks (r = .126, p = .265) and for birth order and tasks it is still not strong (r = .301, p = .006). As noted earlier there are many Level 3 responses to the random definition and Level 1 responses to the lottery question.

In considering the performance of students who answered all five items, no student scored a maximum score of 19. The highest total score was a 17 achieved by a Grade 9 student. This student was S2, who provided a Level 3 response to the survey question on Random, QS1. For the survey item on Luck, QS2, S2 responded at Level 3 in the following fashion including reference to the probability of numbers occurring.

S2: I doubt she'd be able to win Tattslotto twice by using the same numbers because if each set of numbers has a certain chance (e.g. 1/1000000) once one set of numbers has one (won), it is unlikely that they'd come again until (1000000) goes later.

For the interview task Q11, S2 mentioned lack of bias in random selection (Level 4).

S2: It means that the children are just, they are not chosen because they have some special quality or something, they are just picked out any old way it doesn't really matter.... It means that they just pick the numbers out they are not biased towards one number or something. Or they haven't specially chosen the one number to come out, it's just as it happens.

For the interview question on the lottery, Q12, S2 had difficulty resolving the conflict of equal likelihood of outcomes and their perceived spread. This was given a Level 3 code for the final part of the response.

S2: [Writes down, 2, 4, 27, 35, 43,40] I just guessed them. I just sat down and wrote out numbers between 1 and 45. [Well, which ticket do you think is more likely to get all 6 numbers right? Would it be this ticket (Jenny's) or would it be this ticket (Ruth's)?] ... Probably Jenny's because she has a wider range of numbers but I don't know that it would make that much difference. [Do you think they might have the same chance?] I think that they might have about the same chance, it would lean either way.

S2, however, appeared to handle equal likelihood more easily in the birth order task, Q13, with the following Level 4 response.

S2: [Chooses Equally Likely Part (a)] Well, if there is not really any other information saying that it is specifically a hospital mainly for boys or mainly for girls. So you would think that out of 6 babies they would be equally likely. [Chooses Equally Like Part (b)] Because there is the same amount of boys and girls in both of them.

S8 was a Grade 6 student whose total score summed to 16 and who responded at Level 3 for the random interview task, QI1, and at Level 4 for the birth order question, Q13. For survey random question, QS1, S8 responded by giving two examples, "Tattslotto" and "raffle draw," which was a Level 2 response. For the luck question, QS2, the Level 3 response was brief but to the point, "It is as likely to be them as any other numbers." Finally for the lottery interview question, Q12, S8 was confident about equal likelihood, offering the following Level 4 response.

S8: [Writes down 3, 12, 26, 37,43, 32] I just took any that were any where, I didn't make any definite numbers. [Chooses equally likely] Equally because the thing that picks them out is just as likely to pick 1, 2, 3, 4, 5, 6 as if it is going to pick any other number.

These two students displayed overall the highest levels of performance for tasks associated with random processes.

A summary of the correlations between the pairs of tasks is given in Table 13 to indicate the degree of association displayed in the responses of students. The birth order task, Q13, had the least association with the other tasks employed. Although seven of the correlations are significant at the .01 level, the percent of variation explained varies from only 9% for the lottery and birth order interview tasks to 35% for the two questions on random.

Research Question 2: Longitudinal Change

A subset of students who participated in Study 1 was interviewed for a second time three or four years later. All 23 of the students were asked to discuss the meaning of random, QI1. Of these, 12 responded at the same level the second time, 8 responses were Level 3 and only one was at Level 4 each time. Nine students improved their level of response, whereas two Grade 6 students regressed from Level 3 to Level 2. Of those who improved, three were initially in Grade 3 and these students all improved from Level 1 to Level 3, four were in Grade 6, and two in Grade 9. The two Grade 9 students both moved from Level 3 to Level 4.

S33: [First interview] Pick something without a formula, just any old thing or person. [Second interview] A random sample, choose a sample that is not biased so that it doesn't represent one part more than the other. [Grade 9 in first interview]

Twenty-one students answered the lottery question, QI2, in each interview and of these, 12 responded at the same level each time, four at the highest possible and eight at Level 1. The following responses are consistently at Level 1.

S34: [First interview. Chooses Jenny] It is nearly impossible to get it all in a row. [Second interview. Chooses Jenny] Ruth wouldn't have a chance because there would be a slim chance of all those numbers coming up in a row. [Grade 6 in first interview]

Seven students improved levels, four by two or more levels from Level 1. One student improved from Level 1 to Level 4.

S6: [First interview. Chooses Jenny] Because the numbers don't usually come up consecutively. [Second interview. Chooses Equally Likely] Because all of these numbers have the same chance of coming up. [Grade 6 in first interview]

Subsequently two students, a Grade 6 and a Grade 9, regressed by one level.

Only 13 students completed the birth order question, QI3, in the longitudinal interview. The two Grade 3 students regressed from Level 2, whereas the two Grade 9 students improved to Level 4. Of these two Grade 9 students, one moved from Level 3 to Level 4 and the other student improved from Level 1 to Level 4, indicating that they were no longer susceptible to probabilistic or order imbalance.

S35: [First interview. Chooses BBGBGB Part (a)] Because it has got an even number ... but I suppose more days, equal amounts of each are born. [Chooses BBGBGB Part (b)] Because it is very likely, it isn't often that 3 boys and 3 girls come out like that. [Second interview. Chooses Equally Likely for both parts]. I think for it to be in that sequence it is the same [goes on to explain the actual chance of the sequence occurring] 1 in 64. [Grade 9 in first interview]

Of the nine Grade 6 students, three remained at the same level, one at Level 4, whereas one regressed from Level 3 to Level 2, and five improved, two to Level 4.

Overall for all three interview questions there was a trend for improvement over three or four years, with little indication of regression. This is shown in detail in Table 14 for the 57 pairs of responses for the three interview questions. Responses to the questions are denoted by a letter for the item (R for Random, L for Lottery, and B for Birth Order) followed by the initial grade levels for all responses to that item in a given cell. L366, for example, indicates that one Grade 3 and two Grade 6 students responded to the lottery question (QI2) at Level 1 in the initial interview and at Level 2 in the longitudinal interview. Although the numbers are small for a given grade and item, it can be seen that no student initially at Level 4 gave a lower level response later and 45% of responses overall that could improve over the time between interviews, did so. Also, the students originally in Grade 6 gave longitudinal responses whose distribution was not inconsistent with that of the Grade 9 students in the initial interview.

Research Question 3: Cognitive Conflict

Study 3 involved the use of video prompts of earlier students' responses (Study 1) to create cognitive conflict for the new students being interviewed. Fifteen students were prompted with at least one student response that differed from their initial response on the lottery interview question, QI2, and five students were prompted on the birth order question, QI3. In some instances a second prompt was also shown to students as a means for determining the strength of their initial decision.

Lottery interview question, QI2. Of the 15 students presented with a prompt for the lottery interview question, initially 5 gave Level 1 responses, 2 at Level 2, 4 at Level 3, and 4 at Level 4 as described in Table 2. The five students who initially responded at Level 1 were given Level 4 prompts. Four of these students rejected the higher level prompt and were still influenced by the "look' of the numbers as in the order or spread.

S36: [First response. Writes down 14,23, 28, 37, 44, 7. Chooses Jenny] Umm Jenny's I would say because Tattslotto doesn't usually end up being 1, 2, 3, 4, 5, 6 so Jenny's is more logical. [Video Prompt Tony, Figure 2] It's more unlikely to get 1, 2, 3, 4, 5, 6 than it is to get the random numbers. It should be a bit spread out more evenly. [Grade 9]

S21: [First response. Writes down 42, 3, 45, 21, 10, 9. Chooses Jenny] The balls never really go 1, 2, 3, 4, 5, 6 and sometimes they go like 31, 32, 33 and they will go like 42 and then back again. There's more chance of random numbers I think. [Video Prompt Tony, Figure 2] No. Apart from the fact if he did go like 1, 2, 3, 4, 5, 6 someone might think it might have been rigged. [Grade 6]

One Level 1 student who initially chose Jenny's numbers because "It comes out random, you don't see 1, 2, 3, 4, 5, 6 come out that often," attempted to integrate a Level 4 idea into her answer but did not successfully resolve the conflicting ideas.

S37: [Video Prompt Tony, Figure 2] They have the same chance but it is more likely that they will come out in random order rather than consecutive order. The two tickets have the same chance but if you had to back one, you would back the one with random ones because it doesn't usually come out in consecutive numbers. [Grade 9]

For the two students who responded at Level 2, the Level 4 prompts were rejected and the students did not appear to resolve the contradictions apparent in their initial explanations. Of the four students at Level 3, one rejected a lower level response. The other three students passively agreed with both lower and higher level responses. These students did not seem to have the same strength of belief as observed in those students who gave Level 1 or Level 4 responses.

The four students who initially responded at Level 4 were all prompted with lower Level 1 responses and three of the students rejected the lower level responses, preferring their own earlier responses.

S38: [First response. Chooses Equally Likely] It doesn't matter at all you have still got the same chance. That's one set of numbers [Ruth] and that would be another set of numbers [Jenny] and like you if there's a million combinations then you've still got a 1 in a million chance. [Video Prompt Tracey, Figure 2] No I don't think so because that's still, you still have got a 1 in a million chance of getting that number ... and those numbers. [Grade 9]

The other student who initially responded at Level 4 changed his or her argument and accepted a Level 1 response. When given a second prompt at Level 4 this student still favored the Level 1 response.

S9: [First response. Chooses Equally likely] Same chances because each number has got a same chance of getting drawn, so therefore they both have an equal chance. [Video Prompt Terry, Figure 2] I've changed my mind his idea is better. [Video Prompt Tony, Figure 2] I still go with the first kid. [Interviewer ... you are more likely to get a range of numbers rather than just do all of them?] Yes. [Grade 9]

Birth order interview question, QI3. Of the five students (1 in Grade 6 and 4 in Grade 9) presented with a prompt for the birth order interview question, QI3, initially two gave responses at Level 1, one at Level 2, one at Level 3, and one at Level 4. Of the two students who responded at Level 1, one did not accept a Level 4 response and also rejected a Level 2 response, whereas the other started to accept a higher level response but did not make a definite change in response level. When given a Level 4 prompt the student who initially gave a Level 3 response recognized the higher level "equally likely" idea in that both sequences "could happen" but was still influenced by the balance of gender, in Part (a). The student did, however, reject a lower level response.

S26: [Video Prompt Tracey, Figure 3] Well, I sort of said that, I said the BBBBGB could happen but that BGGBGB is more likely because of the numbers, they are even. [Video Prompt Tony, Figure 3] Well that could be a random order like boy, boy, girl, girl, boy, girl or something, that's pretty random. [Grade 9]

The student who initially responded at Level 4 agreed the BGGBGB "looks like" a random order but maintained the sequences were both "equally likely" and had the "same chance."

Overall for the cognitive conflict interviews, students who gave responses at Level 1 generally rejected higher level responses, preferring their own initial responses. Those students who gave responses at Level 4 generally rejected lower level responses, reiterating their initial Level 4 arguments and reasoning. Level 2 students seemed unable to resolve the conflicts or contradictions within their explanations. A characteristic of Level 3 responses was passive agreement with conflicting ideas as presented by the other students.

Discussion

The Discussion focuses on six aspects of this study: the hierarchical aspects of the responses to the five tasks, the association of levels of response across the tasks, longitudinal change, change after cognitive conflict, implications for future research, and implications for teaching.

Understanding for the Five Tasks

Performance on item QS1, the survey task on random, improved with grade, particularly between Grades 3 and 6. These results show a concentration of responses from Levels 0 to 2 with few higher level responses. Given that the nature of the question encouraged students to offer examples this is not surprising. In considering students' understanding of statistical language Moritz et al. (1996), although using a slight variation in coding, reported a similar increase in level of response sophistication across grades for the larger number of students surveyed in the group from which 60 of the students in Study 1 were selected.

Task QI1, the interview question on random, extended the survey question by asking for a meaning, rather than an example, and providing a context for further description. In asking students about random the three elements of these two items (meaning, example, and context) appeared to work well together in that there was a moderately high relationship between tasks QS1 and QI1. Watson et al. (2003) used a survey item that was structured in a fashion that combined the aspects of the survey item, QS1, and Part (a) of the interview task. Using a hierarchical coding scheme similar to that employed in the present study, they found overall levels of response (Grades 3 to 9) with a distribution more similar to that of task QI1 than QS1. Perhaps reflecting the survey environment, 40% of students responded at the equivalent of Level 1 in the present study, with 20% at Level 2, 37% at Level 3, and 3% at Level 4. This provides some support for the view that the more general questions used in the interview setting will elicit higher level responses, even in a survey setting.

Ideas about luck in a lottery setting have received little attention in the literature that considers students' understanding of random concepts. The question used in this study as a survey item, QS2, was adapted from a questionnaire developed by Fischbein and Gazit (1984). Like Fischbein and Gazit, the results of the current study indicate that only a very small proportion of students attribute random lottery outcomes to luck. The majority of responses, however, were at Level 2 and this revealed a belief related to negative recency, that is winning numbers cannot come up again. This misconception is discussed by Kahneman and Tversky (1972) and Shaughnessy (1992) in relation to the representativeness heuristic.

For task QI2, the lottery interview question, the majority of responses occurred at Level 1, indicating that students were influenced by the "look" of the numbers and expected a random sequence of numbers to be varied and spread. Fischbein and Schnarch (1997) reported that the use of the representative heuristic for this item declined as grade level increased. Similarly in this study, by Grade 9 responses were more spread over Levels 2 and 3, with approximately a third of responses at Level 4. Responses at Level 1 prompted the interviewer to ask an additional question, "What numbers would you choose next week?" In Grades 3 and 6 most students indicated that they would choose "different numbers" and, like with the luck question, reasoned that winning numbers would not come up again.

The birth order questions, interview task QI3, have been administered in many forms over the years. In exploring the representativeness heuristic, they have been adapted for several contexts, including birth order and coin tossing. Earlier research (Shaughnessy, 1977; Garfield & delMas, 1991; Kahneman & Tversky, 1972) reported that students selected a sequence like GBGBBG as being more likely than the sequences BGBBBB and BBBGGG. Those studies that asked students to explain their answers report that responses were influenced by the representativeness belief in that alternative sequences a) did not reflect the expected even numbers of boys and girls being born and b) did not reflect the perceived spread of boys and girls. The combined Level 1 responses across grades reported in this study show only 24% of students reasoned with both beliefs based on representativeness which is lower than results reported by Garfield & delMas (1991). A further 21.7% of students, however, indicated that they were susceptible to one or other of the beliefs with only 13.3% reasoning correctly on both sequences. The presence of the largest number of responses (33.7%) at Level 2, giving technically correct multiple choice responses but with simplified reasoning not reflecting the complex nature of the independent events, provides a warning for teachers to explore students' reasoning beyond a choice of alternative. Although response levels improved substantially from Grade 3 in this study, the difference between Grades 6 and 9 was not as great, perhaps indicating that the intuitions supporting responses are not being addressed in the middle school years.

The Association of Performance across Tasks

Although from the point of view of cognitive theory there would be an expectation that students should respond at similar structural levels across different tasks, such was not the case in this study of random processes. The different contexts in which the questions were presented--in survey and interview--contributed to this difference. The advantage of the interview setting over a survey seems clear from two perspectives. First, it is difficult for students not to provide at least some type of response, which the interviewer can then probe further, greatly reducing the number of non-responses. As well, the interview task on random in this study provided a second context, the television setting for a lottery, which gave students another angle from which to draw upon their memories about random processes. Both of these factors contributed to higher levels of response to the interview item than to the survey item concerning the meaning of random.

The other three tasks tapped into widely differing aspects of equally likely random processes, exploring intuitions about luck, the idea of random as spread out, and the classic representative dilemmas associated with a sample having the exact population proportion or an uneven distribution. Whereas most students are comfortable disregarding luck as a factor in winning a lottery, not many can go on to give higher level justifications in terms of equal likelihood of outcomes. This difficulty is also evident in the task to distinguish which of consecutive or spread out numbers are likely to win the lottery. The fact that 46% of students were in both of these categories points to a deficit in the appreciation of the implications of equal likelihood. Lack of understanding did not stop students achieving a Level 2 technically correct response to QS2 but produced the Level 1 incorrect response to QI2. The modal response levels point to the greater difficulty of the context of QI2 for students. Again comparing the modal response level of QI1 on the meaning of random (Level 3) with the two lottery items suggests that the added contextual support in QI1 may have aided students in responding at higher levels.

Although the distribution of responses across levels was the most even for the birth order task, QI3, the spread of data over the cells in Tables 11 and 12 shows that the association of levels of response is not high between Q13 and the other two interview tasks. There was in fact no association between the birth order task and two random items. The nature of the birth order questions, relying as they do on an appreciation of independent compound events may partially explain the lack of association. This distribution of responses to QI3 may represent exposure to classroom experiences such as coin tossing for some students, whereas discussion of random processes and luck may not have taken place.

Differing levels of response on tasks featuring different aspects of the same probability construct were also observed by Garfield and delMas (1991) and Burgess (2000). Both suggested that context was a significant feature and the current research supports this view.

Longitudinal Change

Over the three or four-year period, few students performed at lower levels on the three interview tasks, only two for each of the random and lottery questions and three for the birth order task. For the random task, of the 22 who could improve their performance, 41% did so. For the lottery question 37% of the 17 who could improve did and for the 12 on the birth order question, 58% improved. Overall this represents an improvement rate of 45% for the three tasks. The observed improvement over time suggests a positive development in understanding reflected in nearly half of the responses over a three- or four-year period. This and the similarity of pattern of responses for the Grade 6 students in longitudinal interviews to the earlier Grade 9 students supports the suggestion of developmental change also being displayed by the original cohorts in this study. The small number of longitudinal interviews means that this hypothesis must remain tentative but the issue deserves further research. This is particularly the case since some studies have suggested a lack of change across the school years in understanding random phenomena.

It is interesting to compare the rates of improvement over time for these tasks with the rates for tasks associated with other topics in the chance and data curriculum. Improvement here was similar to that for beliefs about fair dice (47%) and strategies for determining the fairness of dice (39%) (Watson & Moritz, 2003), topics closely related to ideas about random behavior. Rates were also similar to improvement on representation of data with pictographs (38%) and interpreting pictographs (58%), but much less than the improvement in predicting from pictographs (90%) (Watson & Moritz, 2001b). Greater improvement rates were also observed for the concepts related to average (79%) (Watson & Moritz, 2000b), sampling (74%) (Watson, 2004), and beginning inference (65%) (Watson, 2001). Two reasons are suggested for the difference in improvement rates. One is that a topic such as average, which contributes to many of the concepts covered in the tasks including prediction, is included in the middle school curriculum completed by many of the students during the three or four years between interviews. The other is that ideas related to chance and probability are notoriously difficult to change (Fischbein & Gazit, 1984) and the improvement rates here may reflect that difficulty.

Cognitive Conflict

The sample size for students exposed to cognitive conflict for two of the interview questions was small and hence it is not possible to suggest generalizations. It is of interest, however, that presenting students with higher level responses did not have the desired effect. No student accepted with confidence a higher level argument than that originally offered. The likely explanation for this is that beliefs based on intuitions about random behavior cannot be changed without considerable first-hand empirical experience. An opinion expressed in a few seconds, especially by another student and not an authority figure, is easy to dismiss. If the students being interviewed realize that their responses are based on intuition, then so may the beliefs expressed on the video clip be based on the intuitions of the other person. There was no opportunity during the interview to test beliefs with trials. In comparison with the longitudinal interviews in this report, the intervening period of three or four years obviously had a more positive effect in producing higher level responses. In comparison with other protocols that employed cognitive conflict, this one on random processes was the least successful (Watson, 2002a, 2002b; Watson & Moritz, 2001a, 2001b). The one student in this study (S9) who was persuaded by a lower level response was the only example of such an influence over the five topics analyzed, including chance measurement, sampling, pictographs, and comparing two data sets.

The outcomes with respect to cognitive conflict are perhaps not surprising in the light of the observations of responses to random tasks by Fischbein and Gazit (1984) and Fischbein and Schnarch (1997). If it is unusual to observe improved performance across grades and if over three or four years less than half of students are likely to improve, then to expect improvement in a few minutes is probably unrealistic.

Implications for Future Research

Several suggestions for future research arise from the outcomes of these related studies. First, wherever possible it is advisable to interview students on topics related to random behavior rather than rely on written survey responses. Students appear more willing in interview setting to suggest a tentative response even if they are unsure. In a survey they are likely to leave the question blank. Providing a context within which to discuss the concept of random is also helpful to students.

In an interview setting, if cognitive conflict is to be employed, it would appear that time must also be provided to allow for experimentation with random generators. For the birth order task it would be possible to experiment with tossing six coins in order many times and record the outcomes. Using a computer simulation would be more efficient but in this case care must be taken to ensure that students understand how the simulation works and what outcomes are being recorded, especially if this is done by the computer and not the student.

Following the outcomes of this study and those of Fischbein and Gazit (1984), it would appear that a research design employing a strong instructional intervention, perhaps over a period of a few weeks, would be more likely to achieve positive outcomes in a post-instruction interview. Computer simulation for the birth order task would appear promising, along with a thorough discussion of independent events. For tasks related to lotteries, studying distributions of outcomes from simulations may be helpful.

Implications for Teaching

Falk and Konold (1994) contend that presenting ideas about random to students involves "undertaking the challenge of bringing up the doubts and difficulties that students will predictably have (p. 2)." The colloquial ideas associated with random in everyday life need to be discussed in the classroom and compared and contrasted with statistically appropriate descriptions. Perhaps the most useful from the middle school level is that of David Moore (1990).

Phenomena having uncertain individual outcomes but a regular pattern of
outcomes in many repetitions are called random. 'Random' is not a
synonym for 'haphazard,' but a description of a kind of order different
from the deterministic one that is popularly associated with science and
mathematics. Probability is the branch of mathematics that describes
randomness. (p. 98)

Much discussion of expectation and variation should follow exposure to this description. As Metz (1998) points out for her study,

The construct of randomness addressed in this study involves an
integration of the uncertainty and unpredictibility of a given event,
with patterns manifested over many repetitions of the event. These data
indicate that children and adults frequently fail to integrate the
uncertainty with the patterns, instead either interpreting the patterns
in deterministic form or recognizing the uncertainty apart from the
associated patterns. Although the first error overestimates the
information given, the second error underestimates it. (p. 349)

Overall the suggestions made in the previous section about teaching intervention as part of research apply to classroom instructions generally. If a goal of the chance part of the data and chance curriculum is for students to have an adequate understanding of random processes, then appropriate, explicit teaching activities must be incorporated. These must be accompanied by extensive discussion and comparison of in-school and out-of-school observation of random phenomena.

Acknowledgments

This research was funded by Australian Research Council Grants No. AC9231385, W0009108, A79800950, and DP02088607. Jonathan Moritz conducted some interviews in Study 1, and all of the interviews in Study 2 and Study 3; he also set up the spreadsheet environment for the analysis.

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Jane M. Watson and Annaliese Caney

University of Tasmania 

Table 1 Number of Participants in Each Grade and Study

                                                      Study 3
             Study 1 Initial    Study 2 Longitudinal  Cognitive Conflict
                     South                South
Grade      Tasmania  Australia  Tasmania  Australia   Tasmania

3          24         3          3        2            1
6*         30         8         11        3            7
9          30         4          4        0            7
Sub total  84        15         18        5           15
Total           99              23 (subset of         15 (subset of
                                Study 1)              Study 1)

*Dala collected in South Australia were from students in Grade 5 and 7.
These grades have been combined with Grade 6 for analysis.

Table 2 Global Descriptions of Response Levels for Survey and Interview
Items.

                                      Random
      Response     Global             (Interview &     Lottery
Code  Level        Description        Survey)          (Interview)

4     Relational   Integrated         Multiple         Not influenced by
                   understanding as   qualification    consecutive order
                   required by the    of random        of numbers and
                   question.          integrated with  ideas of
                   Appreciation of    good example(s)  variation/spread
                   random/chance      and mention of   with explicit
                   outcomes, not      "bias" or        mention of all
                   influenced by      "fairness."      numbers having an
                   order or balance.                   equal chance. May
                                                       include ideas on
                                                       sets of numbers
                                                       and chance.
3     Multi-       Recognize          A qualified      Express a
      structural   regularity of      idea about       generalized idea
                   chance.            random           about chance
                   Inconsistent       integrated with  with qualitative
                   cognition of       an example.      chance
                   balance or order                    statements.
                   as issues.
                   Sequential ideas
                   (multiple) in
                   definitions.
2     Uni-         Single ideas       A single idea    Express
      structural   about random or    about random or  contradictory
                   luck or broad      an example.      ideas and show no
                   chance reasoning                    recognition of
                   that "anything                      contradiction or
                   could happen."                      broad chance
                                                       reasoning with no
                                                       qualified chance
                                                       statement.
1     Ikonic       Intuitive ideas    An intuitive     Influenced by
                   about random.      response with    consecutive order
                   Susceptible to     no clear         of numbers and
                   both balance and   definition.      expected
                   order.                              variation/spread
                                                       of numbers.
                                                       Choose Jenny's
                                                       numbers.
0     No response  No response or no  No response.     Idiosyncratic
                   explanation. Any                    responses and no
                   reasoning that is                   reasoning.
                   inappropriate or
                   idiosyncratic.

Code  Birth Order (Interview)                   Luck (Survey)

4     Not susceptible to probabilistic and      Not observed.
      order imbalance. Ideas may extend to
      include sample size. Choose equally
      likely with appropriate reasoning.
3     Susceptible to probabilistic or order     Disagreement with
      imbalance. Recognizes conflict in random  luck accompanied by a
      behavior in one but not all contexts.     qualitative chance
      Choose a combination of sequences BGGBGB  statement or an idea
      and equally likely.                       about random.
2     Broad chance reasoning that "anything     Broad chance reasoning
      could happen" with no qualified ideas.    that "anything could
      Choose Equal/Equal.                       happen" or disagreement
                                                with luck either
                                                implicitly or
                                                explicitly.
1     Susceptible to both probabilistic and     An intuitive response
      order imbalance. Strict views as          indicating belief in
      reflected in small samples. Choose        luck.
      BGGBGB pattern consistently.
0     No response or no explanation. Any        Idiosyncratic.
      reasoning that is inappropriate or
      idiosyncratic.

Table 3 Response Levels Across Grades for the Random Survey Question,
QS1

          Response levels
Grade  0   1   2   3  Total

3      11   8   2  1  22
6       5   8  12  2  27
9       1   5  10  6  22
Total  17  21  24  9  71

Table 4 Levels of Response Across Grades for Meaning of Random Interview
Question, QI1

          Response levels
Grade  0  1   2   3   4  Total

3      0  15   4   7  0  26
6      1   5  11  16  1  34
9      0   1   5  21  5  32
Total  1  21  20  44  6  92

Table 5 Levels of Response for Meaning of Random in Survey and Interview
Questions

Interview        Survey response levels
response levels  0   1   2   3  Total

0                 1   0   0  0   1
1                 8   7   2  0  17
2                 4   5   6  0  15
3                 2  10  16  7  35
4                 0   0   1  2   3
Total            15  22  25  9  71

Table 6 Response Levels Across Grades for the Luck Survey Question, QS2

        Response levels
Grade  0  1  2   3   Total

3      5  4  17   0  26
6      0  2  26   3  31
9      0  2  14  11  27
Total  5  8  57  14  84

Table 7 Response Levels Across Grades for the Lottery Interview
Question, QI2

         Response levels
Grade  0  1   2   3   4   Total

3      1  22   2   1   0  26
6      1  20   9   4   4  38
9      0  14   5   5  10  34
Total  2  56  16  10  14  98

Table 8 Levels of Response for Luck Survey Question and Lottery
Interview Question

Lottery response  Luck response levels
levels            0  1  2   3   Total

0                 0  1   1   0   2
1                 5  5  39   2  51
2                 0  1   9   4  14
3                 0  1   4   1   6
4                 0  0   3   7  10
Total             5  8  56  14  83

Table 9 Levels of Response for Meaning of Random and Lottery Interview
Questions

Lottery response  Random response levels
levels            0  1   2   3   4  Total

0                 0   1   1   0  0   2
1                 1  18  11  21  1  52
2                 0   1   5   8  0  14
3                 0   0   2   5  2   9
4                 0   0   1  10  3  14
Total             1  20  20  44  6  91

Table 10 Response Levels Across Grades for the Birth Order Interview
Question, QI3

         Response levels
Grade  0  1   2   3   4   Total

3      4   3  11   2   0  20
6      1   8  10   6   4  29
9      1   9   7  10   7  34
Total  6  20  28  18  11  83

Table 11 Levels of Response for Meaning of Random and Birth Order
Interview Questions

Random response  Birth Order response levels
levels           0  1   2   3   4   Total

0                0   0   0   0   1   1
1                4   2   6   2   0  14
2                0   2   7   5   3  17
3                2  13  14   9   4  42
4                0   1   1   2   2   6
Total            6  18  28  18  10  80

Table 12 Levels of Response for Birth Order and Lottery Interview
Questions

Lottery          Birth Order response levels
response levels  0  1   2   3   4   Total

1                5  15  16   8   4  48
2                0   1  10   2   1  14
3                1   0   1   2   3   7
4                0   4   1   6   3  14
Total            6  20  28  18  11  83

Table 13 Correlation between Levels of Response on the Five Tasks

                       Random   Luck    Random     Lottery
                       Survey   Survey  Interview  Interview

Luck Survey             .314**
Random Interview        .592**  .359**
Lottery Interview       .347**  .483**  .481**
Birth Order Interview  -.162    .284*   .126       .301**

*p [less than or equal to] .05, **p [less than or equal to] .01

Table 14 Longitudinal Change in Level of Response for the Random (R),
Lottery (L), and Birth Order (B) Questions for Each Student by Initial
Grade (3, 6, or 9).

Level at Initial
Interview         1          2         3          4        Total

Level at
Longitudinal
Interview

0                                                               [1]
                             B3                             1 B
                  R3                                        1 R
1                 L33666666  L6                             9 L [12]
                  B6         B3                             2 B
                  R6         R66       R66                  5 R
2                 L366                 L9                   4 L [10]
                                       B6                   1 B
                  R333       R6        R36666699           12 R
3                 L3         L6                             2 L [17]
                  B6         B66                            3 B
                             R6        R699       R6        5 R
4                 L69                             L6669     6 L [17]
                  B669                 B69        B6        6 B
                  5 R        4 R       13 R       1 R
Total             14 L [24]  2 L [10]  1 L [17]   4 L [6]       [57]
                  5 B        4 B       3 B        1 B