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# Classroom Case Studies, Grades 3-5 Part A: Statistics as a Problem-Solving Process (30 minutes)

A data investigation should begin with a question about a real-world phenomenon that can be answered by collecting data. After the children have gathered and organized their data, they should analyze and interpret the data by relating the data back to the real-world context and the question that motivated the investigation in the first place. Too often, classrooms focus on the techniques of making data displays without engaging children in the process. However, it is important to include children in all aspects of the process for solving statistical problems. The process studied in this course consisted of four components:

Children often talk about numbers out of context and lose the connection between the numbers and the real-world situation. During all steps of the statistical process, it is critical that students not lose sight of the questions they are pursuing and of the real-world contexts from which the data were collected.

When viewing the video segment, keep the following questions in mind:
• How do the students in this classroom apply the first two components of the statistical process? What statistical question are the students trying to answer? How were the data collected?
• As the fifth graders move onto the next two components of the statistical process — analysis and interpretation — what issues do you think will come up?
• Thinking back to the big ideas of this course, what are some statistical ideas these students are likely to encounter through their investigation of this situation?

See Note 2 below.

Video Segment
In this video segment, teacher Suzanne L’Esperance applies the mathematics she learned in the Data Analysis, Statistics, and Probability course to her own teaching situation. She starts by establishing the context for her students to investigate family size, telling them about her friend who is in construction and how he needs help from the students in the class. The students consider the context and then begin to collect the data.

Problem A1
Answer the questions you reflected on as you watched the video:
• How do the students in this classroom apply the first two components of the statistical process?
• What statistical question are the students trying to answer?
• How did the students collect their data?
• As the students move on to analysis and interpretation of their data, what issues do you think will come up?
• What statistical ideas are students likely to encounter as they investigate this situation?

Problem A2
In this video, Ms. L’Esperance establishes a rich and elaborate real-world context to situate the students’ investigation of family size. How do you think the class would have responded if she had not constructed a context for the investigation and instead had simply said, “Today we are going to investigate family size; how many people are in your family?” What is the impact on the students’ level of engagement?

Problem A3
Too often, students lose the connection between the numbers and the real-world situation once they have gathered their data. How might the richer context provided by Ms. L’Esperance reinforce the connection between the data and the real-world phenomenon being studied, and prevent students from working with mere numbers out of context?

Problem A4
What are some ways in which this richer context will support students’ reasoning as they “interpret the results”?

Problem A5
Why do you think Ms. L’Esperance phrased the question about family size as “How many people live in the house that you slept in last night,” as opposed to simply “How many people are in your family?” With your own students, how would you define “family”? See Note 3 below.

When engaging students in the process of statistical problem solving, students must consider what to measure and how to measure it to ensure accuracy in collecting their data. In this lesson, Ms. L’Esperance defined “family” for her students. But, it is also important to give students a chance to form — or to help form — their own definitions for the purpose of their investigations.

Problem A6
How would you facilitate a discussion with your students on what constitutes a “family”? Describe some of the sensitive issues that might arise and how you would handle them.

### Notes

Note 2
Before examining specific problems at this grade level with an eye toward statistical reasoning, you will watch a teacher (who has also taken the course) teaching in her classroom. The purpose in viewing the video is not to reflect on the teacher’s methods or teaching style. Instead, look closely at how the teacher brings out statistical ideas while engaging her students in statistical problem-solving. You might want to review the four-step process for solving statistical problems. What are the four steps? What characterizes each step?

You might want to review the four-step process for solving statistical problems. What are the four steps? What characterizes each step?

Note 3
The 2000 United States Census defines a household as one or more persons living in a housing unit. One person who owns or rents the residence is designated as the householder. For the purposes of examining family and household composition, two types of households are defined: family and non-family. A family household has at least two members related by blood, marriage, or adoption, one of whom is the householder. A non-family household can either be a person living alone or a householder who shares the housing unit with non-relatives only — for example, boarders or roommates. The non-relatives of the householder may be related to one another.

### Solutions

Problem A1
a.
The question is, “How many people are in a family?”
b. Each child was told to use connecting cubes to show the number of people that live in his or her house.
c. One might expect that the issue of “center” (median) would arise when determining the typical size of families, as well as the issue of variation in the data.
d. Some statistical ideas are the nature of data, quantitative variables, variation, range, measures of center, sampling, making a line plot, and interpreting a line plot.

Problem A2
It is likely that this rich context more fully engages children because there is a clear purpose for investigating family size. The context also increases the authenticity of the task. There is a real-world rationale for why a person in a specific profession would need to know the size of families or households in a particular area. While children might also be curious about the number of people in each of their families, they do not have a reason — other than their interest — to extend the investigation beyond their classroom.

Problem A3
The rich context grounds students more firmly in the situation. With the clear purpose of examining family size and the fact that the data are about them, they more readily analyze the data with the real-world situation in mind than they would if they were just thinking about numbers out of context.

Problem A4
Again, the rich context grounds students in the situation. They are invested in helping the teacher’s friend and have a clear purpose for interpreting the data so that they can make an appropriate recommendation. The students are also able to draw on their own knowledge about the neighborhood and about family size. Thus, as they interpret the results, they are more likely to raise issues, think beyond their own classroom sample, and become curious about the larger population.

Problem A5
The teacher’s phrase resembles the definition of a “household” as set by the 2000 United States census. Answers to the second question will vary, but might include “all the people you spend holidays with,” “the people you’re related to,” and “your mother, father, sisters, and brothers.”

Problem A6
Sensitive issues might involve brothers and sisters who no longer live in the same household, parents or siblings who have died, single- and dual-parent households, same-sex and different-sex guardians, or joint-custody situations. These are all aspects of people’s lives, and are good examples of the importance of definitions when collecting data.