In Exercises 9 and 10, determine whether the study is an observational study or an experiment. Explain.


To study the effect of using digital devices in the classroom on exam performance, researchers divided 726 undergraduate students into three groups, including a group that was allowed to use digital devices, a group that had restricted access to tablets, and a control group that was “technologyfree.” (Source: Massachusetts Institute of Technology)

Determine whether each number describes a population parameter or a sample statistic. Explain.

In a recent year, the average evidence-based reading and writing score on the SAT was 528. (Source: College Board)

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Questioning teachers as they leave a faculty lounge, a researcher asks 45 of them about their teaching styles.

What Would You Do? You work at a bank and are asked to recommend the amount of cash to put in an ATM each day. You do not want to put in too much (which would cause security concerns) or too little (which may create customer irritation). The daily withdrawals (in hundreds of dollars) for 30 days are listed. 72 84 61 76 104 76 86 92 80 88 98 76 97 82 84 67 70 81 82 89 74 73 86 81 85 78 82 80 91 83

If you are willing to run out of cash on 10% of the days, how much cash should you put in the ATM each day? Explain.

In Exercises 1 and 2, identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Using random digit dialing, researchers asked 1090 U.S. adults their level of education.

In Exercises 11 and 12, determine whether the data are qualitative or quantitative, and determine the level of measurement of the data set.

The six top-earning states in 2019 by median household income are listed. (Source: U.S. Census Bureau)

1. Maryland 2. New Jersey 3. Hawaii

4. Massachusetts 5. Connecticut 6. Alaska

Which part of the survey described in Exercise 31 represents the descriptive branch of statistics? What conclusions might be drawn from the survey using inferential statistics?

Determine whether the data are qualitative or quantitative, and determine the level of measurement of the data set. Explain your reasoning.

The numbers of employees at fast-food restaurants in a city are listed.

20 11 6 31 17 23 12 18 40 22 13 8 18 14 37 32 25 27 25 18

Determine whether the survey question is biased. If the question is biased, suggest a better wording.

Do you agree that the town’s ban on skateboarding in parks is unfair?