CH 1
17. Suppose a researcher would like to determine whether one grade of gasoline produces better
gas mileage than another grade. Twenty cars are randomly divided into two groups, with 10 cars
receiving one grade and 10 receiving the other. After many trips, average mileage is computed
for each car. a. Would it be easier to detect a difference in gas mileage for the two grades if the
20 cars were all the same size, or would it be easier if they covered a wide range of sizes and
weights? Explain. b. What would be one disadvantage to using cars that were all the same size?
●It would be easier to detect a difference in gas mileage for the two grades if the 20 cars
were all the same size because if all the cars were the same size, you can clearly see the
difference between the gasolines if all of the cars had the same mileage, etc. One
disadvantage would be
22. Refer to the definitions of sample and population on page 7. For each of the following,
explain who is in the sample, and what population you think is represented. a. Case Study 1.1,
testing the effect of a heartbeat sound in a baby nursery. b. Case Study 1.2, testing the effect of
taking aspirin on heart attack rates.
●A. The sample in this case study would be the babies in the nursery at the New York City
Hospital who had the continuous sound of a human heartbeat playing on the speaker. The
population in this case would be both of the groups in the nursery who were studied.
●B. The sample in this case study would be the group of men taking the aspirin pill. The
population would be the two groups of the men who took the aspirin pill and the placebo
pill with no active ingredient.
CH 2
8. (change scenario to a wine company that is planning to fund a telephone survey of
attitudes about decreasing the age for purchasing/drinking wine to 18 years old),
In each of the following phases of the survey, should the company disclose who is funding the
study? Explain your answer in each case. a. When respondents answer the phone, before they are
interviewed. b. When the survey results are reported in the news. c. When the interviewers are
trained and told how to conduct the interviews.
●A. No, the respondents should not be told the funding of the study before they are
interviewed because it may influence the respondents original answer, and will make the
results biased.
●B. Yes, the company should reveal who is funding the study when the results are reported
in the news because this gives the respondents and the interviewers the full story and data
about the survey they took, giving them a disclosure.
●C. No, the interviewer should not be told who is funding the story because this can
influence the way they interview their respondents. They can be more manipulative,
which can lead to bias results as well.
