Question 1: Formulating questions and collecting data

Energy drinks and sleep survey

Units 1 and 2
10 points
About 22 minutes

You can use a calculator on this question, just like on exam day.

A multi-part question about a study's design: you identify sampling methods or study types, explain whether results can be generalized or show cause and effect, describe or choose a display, and write a valid investigative question. It focuses on Practices 1 and 2. On the exam: Question 1 of 4 (official name: Multi-Focus on Practices 1 and 2). Section II has 4 free-response questions in 90 minutes (50% of the score); each question is worth 10 points and 12.5% of the score. The exam is fully digital in Bluebook, a graphing calculator with statistical capabilities is expected, and the formula sheet and tables are provided.

The question and its sources

Show the work that leads to each answer, and explain your reasoning in the context of the situation. A graphing calculator with statistical capabilities, the formula sheet and the statistical tables are available. Use the information given to answer parts A through F, and label any subparts (for example, i and ii).

The sleep survey

A health researcher selected a random sample of 600 students from the 9,400 students enrolled in a large school district's high schools. Each selected student answered two questions: "Do you drink an energy drink at least once a week?" and "On a typical school night, do you sleep at least 8 hours?" The results are in the table.

Source: Hypothetical scenario

Weekly energy drink use and sleep

Drinks an energy drink weekly	Sleeps at least 8 hours	Sleeps less than 8 hours	Total
Yes	52	108	160
No	231	209	440
Total	283	317	600

Source: Hypothetical data

Suggested time: 22 minutes

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Part (A)

2 points

(i) Identify the type of study the researcher conducted. (ii) Identify the two variables in the study, and classify each as categorical or quantitative.

Your answer to part (A)

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Part (B)

1 point

Explain why the results of this study can be generalized to all high school students in the district.

Your answer to part (B)

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Part (C)

1 point

A local news site reports on the study with the headline "Energy drinks cause teens to lose sleep." Explain why the study does not support this headline. Include a possible confounding variable in your explanation.

Your answer to part (C)

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Part (D)

2 points

The researcher wants a graph that compares the sleep of students who drink energy drinks weekly with the sleep of students who don't. (i) Identify an appropriate graphical representation. (ii) Describe the graph you would construct from the table. Include what each bar represents and the values that determine the bar heights or segments.

Your answer to part (D)

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Part (E)

1 point

Before choosing a random sample, the researcher had considered surveying only the students who attend a 7:00 a.m. study hall before school. Explain how this sample could lead to a biased estimate of the proportion of district high school students who sleep at least 8 hours on a typical school night.

Your answer to part (E)

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Part (F)

3 points

The researcher wants to investigate whether there is an association between weekly energy drink use and getting at least 8 hours of sleep. Determine a valid investigative question for this study. Make sure your question includes all three components of a valid investigative question.

Your answer to part (F)

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