AP Stats - Unit 3 Review - Collecting Data

A public opinion poll in Ohio wants to determine whether or not registered voters in the state approve of a measure to ban smoking in all public areas. They select a simple random sample of fifty registered voters from each county in the state and ask whether they approve or disapprove of the measure.  This is an example of

• Stratified Random Sample

• Cluster Sampling

• Simple Random Sample

• Systematic Random Sampling

• Multistage Sampling

 You want to conduct a survey to determine the types of exercise equipment most used by people at your health club.  You plan to base your results on a random sample of 40 members.  Which of the following methods will generate a random simple random sample of 40 of the members?

• Mail out surveys to every member and use the first 40 that are returned as your sample.

• Randomly pick a morning and survey the first 40 people who come in the door that day.

• Divide the number of members by 40 to get a value k.  Choose one of the first kth name on the list using a random number generator.  Then choose every kth name on the list after that name.

• Put each member’s name on a slip of paper of randomly select 40 slips.

• Get the sign-in lists for each day of the week, Monday through Friday.  Randomly choose 8 names from each day for the survey.

An electronics firms wants to survey its employees to determine their attitudes toward employee compensation.  They obtain the sample for the survey by randomly selecting one of the first 20 names on an alphabetical list of employees and then select each 20^th name on the list from then on.  This is an example of which type of sampling design?

• simple random sample

• cluster sample

• stratified random sample

• convenience sample

• systematic sample

A high school statistics class wants to conduct a survey to determine what percentage of students in the school would be willing to pay a fee for participating in after-school activities.  Twenty students are randomly selected from each of the freshman, sophomore, junior, and senior classes to complete the survey.  This plan is an example of which type of sampling?

• cluster

• convenience

• simple random

• stratified random

• systematic

In a famous study from the late 1920s, the Western Electric Company wanted to study the effect of lighting on productivity.  They discovered that worker productivity increased with each change of lighting, whether the lighting was increased or decreased.  The workers were aware that a study was in progress.  What is the most likely cause of this phenomenon? 

• response bias

• absence of a control group

• lack of randomization

• sampling variation

• undercoverage

An advice columnist asks readers to write in about how happy they are in their marriage.  The results indicate that 79% of those responding would not marry the same partner if they had it to do all over again.  Which of the following statements is most correct?

• It’s likely that this result is an accurate reflection of the population.

• It’s likely that this result is higher than the true population proportion because persons unhappy in their marriages are most likely to respond.

• It’s likely that this result is lower than the true population proportion because persons unhappy in their marriages are unlikely to respond.

• A.      It’s likely that the results are not accurate because people tend to lie in voluntary response surveys.

• There is really no way of predicting whether the results are bias or not.

The Physicians’ Health Study, a large medical experiment involving 22,000 male physicians, attempted to determine whether aspirin could help prevent heart attacks.  In this study, one group of about 11,000 physicians took an aspiring every other day, while a control group took a placebo.  After several years, it was determined that the physicians in the group that took aspiring has significantly fewer heart attacks than the physicians in the control group.  Which of the following statements explains why it would not be appropriate to say that everyone should take an aspirin every other day?

I.                  The study included only physician, and different results may occur in individuals in other occupations.

II.                The study included only males and there may be different results for females.

III.               Although taking aspirin may be helpful in preventing heart attacks, it may be harmful to some other aspects of health.

• I only

•  II only

• III only

• II and III only      

•  I, II, and III

Which of the following can be used to show a cause-and-effect relationship between two variables?

• A census

• A controlled experiment

• An observational study

• A sample survey

• A cross-sectional survey

A study of existing record of 27,000 automobile accidents involving children in Michigan found that about 10 percent of children who were wearing a seatbelt (group SB) were injured and that about 15 percent of children who were not wearing a seatbelt (group NSB) were injured.  Which of the following statements should NOT be included in a summary report about this study?

• Driver behavior may be a potential confounding factor.

• The child’s location in the car may be a potential confounding factor.

• This study was not an experiment, and cause-and-effect inferences are not warranted.

• This study demonstrates clearly that seat belts save children from injury.

• Concluding that seatbelts save children from injury is risky, at least until the study is independently replicated.

Variables are considered to be confounded if

• randomization wasn’t used in the setting up the initial experimental study.

• their effects on the response variable cannot be separated.        

• the response variable is controlled by a placebo.

• more than one additional treatment group is included in the experiment.             

• they are both studied as part of the experiment