AP Stats Unit 3 Review

Data were collected in 20 cities on the percentage of women in the workforce. Data were collected in 1990 and again in 1994. Gains, or losses, in this percentage were the measurement upon which the studies, conclusions were to be based. What kind of design was this?

I. A matched pairs design

II. An observational study

III. An experiment using a block design

• I only

• II only

• III only

• I and III only

• I and II only

You want to do a survey of members of the senior class at your school and want to select a simple random sample. You intend to include 40 students in your sample. Which of the following approaches will generate a simple random sample?

• Write the name of each student in the senior class on a slip of paper and put the papers in a container. Then randomly select 40 slips of paper from the container.

• Assuming that students are randomly assigned to classes, select two classes at random and include those students in your sample.

• From a list of all seniors, select one of the first 10 names at random. Then select every nth name on the list until you have 40 people selected.

• Select the first 40 seniors to pass through the cafeteria door at lunch.

• Randomly select 10 students from each of the four senior calculus classes.

Which of the following is (are) important in designing an experiment?

I. Control of all variables that might have an influence on the response variable

II. Randomization of subjects to treatment groups

III. Use of a large number of subjects to control for small-sample variabitility

• I only

• I and II only

• II and III only

• I, II, and III

• II only

Your company has developed a new treatment for acne. You think men and women might react differently to the medication, so you seperate them into two groups. Then the men are randomly assigned to two groups and the women are randomly assigned to two groups. One of the two groups is given the medication and the other is given a placebo. The basic design of this study is

• completely randomized

• blocked by gender

• completely randomized, blocked by gender

• randomized, blocked by gender and type of medication

• a matched pairs design

A double-blind design is important in an experiment because

• There is a natural tendency for subjects in an experiment to want to please the researcher

• It helps control for the placebo effect

• Evaluators of the responses in a study can influence the outcomes if they know which subjects are in the treatment gorup and which are in the control group

• Subjects in a study might react differently if they knew they were receiving an active treatment or a placebo

• All of the above are reasons why an experiment should be double-blind.

Which of the following is not an example of a random sample

• You are going to sample 10% of a group of students. You randomly select one of the first 10 students on an alphabetical list and then select every 10th student after that on the list

• You are a sports-talk radio host interested in opinions about whether or not Pete Rose should be elected to the Baseball Hall of Fame, even though he has admitted to betting on this own teams. You ask listeners to call in and vote.

• A random sample of drivers is selected to receive a questionnaire about the manners of Department of Motor Vehicle employees

• In order to determine attitudes about the Medicare Drug Plan, a random sample is drawn so that each age group (65-70, 70-75, 75-80, 80-85) is represented in proportion to its percentage in the population

• In choosing respondents for a survey about a proposed recycling program in a large city, interviewers choose homes to survey based on rolling a die. If the die shows a 1, a house is selected. If the dies shows a 2-6, the interviewer moves to the next house.

Which of the following is true of an experiment but not for an observational study?

• A cause-and-effect relationship can be more easily inferred

• The cost of conducting it is excessive

• More advanced staitstics are needed for analysis after the data are gathered

• By law, the subjects need to be informed that they are part of a study

• Possible confounding variables are more difficult to control

A study showed that persons who ate two carrots a day had significantly better eyesight than those who ate less than one carrot a week. Which of the following statements is (are) correct?

I. This study provides evidence that eating carrots contributes to better eyesight

II. The general health consciousness of people who eat carrots could be a confounding variable

III. The is an observational study and not an experiment

• I only

• III only

• I and II only

• II and III only

• I, II, and III

Which of the following situations is a cluster sample?

• Survey five friends concerning their opinions of the local hokey team

• Take a random sample of five voting precincts in a large metropolitan area and do an exit poll at each voting site

• Measure the length of time each fifth person entering a restaurant has to await to be seated

• From a list of all students in your school, randomly select 20 to answer a survey about Internet use

• Identify four different ethnic groups at your school. From each group, choose enough respondents so that the final sample contains roughly the same proportion of each group as the school population

The term used to describe the bias that occurs if some segment of a population is systematically excluded from a sample is

• Undercoverage

• Response Bias

• Nonresponse Bias

• Voluntary Response Bias

• Convenience Sampling