To test the effect of music on productivity, workers are observed. For one month background

music is played. For another month, no music is played. This is an example of

An experiment was designed to investigate the effect of the amount of water and seed variety upon

subsequent growth of plants. Each plant was potted in a clay plot, and a measured amount of water

was given weekly. The height of the plant at the end of the experiment was measured. Which of the

following is not correct?

Randomization was used to even out the effect of other possible factors upon the growth of the

plants.

What electrical changes occur in muscles as they get tired? Student subjects hold their arms above

their shoulders as long as they can. Meanwhile, the electrical activity in their arm muscles is

measured.

This is

The Community Intervention Trial for Smoking Cessation (COMMIT) asked whether a

community-wide advertising campaign would reduce smoking. The researchers located 11 pairs of

communities that were similar in location, size, economic status, and so on. One community in

each pair participated in the advertising campaign and the other did not. This is

Suppose the Richmond-Times Dispatch asks a sample of 150 Richmonders their opinions on the

quality of life in Richmond. Is this study an experiment? Explain why or why not.

Suppose the Richmond-Times Dispatch asks a sample of 150 Richmonders their opinions on the

quality of life in Richmond. Identify the sample and the population in this study.

Read the following brief article about aspirin and alcohol. Aspirin may enhance impairment by alcohol

Aspirin, a long time antidote for the side effects of drinking, may actually enhance alcohol’s effect,

researchers at the Bronx Veterans’ Affairs Medical Center say.

In a report on a study published in the Journal of the American Medical Association, the researchers

said they found that aspirin significantly lowered the body’s ability to break down alcohol in the

stomach.

As a result, five volunteers who had a standard breakfast and two extra-strength aspirin tablets an

hour before drinking had blood alcohol levels 30 percent higher than when they drank alcohol alone.

Each volunteer consumed the equivalent of a glass and a half of wine.

That 30 percent could make the difference between sobriety and impairment, said Dr. Charles S.

Lieber, medical director of the Alcohol Research and Treatment Center at the Bronx center, who was

co-author of the report with Dr. Risto Roine. Does this article describe an experiment or an observational study? Explain.

Read the following brief article about aspirin and alcohol. Aspirin may enhance impairment by alcohol

Aspirin, a long time antidote for the side effects of drinking, may actually enhance alcohol’s effect,

researchers at the Bronx Veterans’ Affairs Medical Center say.

In a report on a study published in the Journal of the American Medical Association, the researchers

said they found that aspirin significantly lowered the body’s ability to break down alcohol in the

stomach.

As a result, five volunteers who had a standard breakfast and two extra-strength aspirin tablets an

hour before drinking had blood alcohol levels 30 percent higher than when they drank alcohol alone.

Each volunteer consumed the equivalent of a glass and a half of wine.

That 30 percent could make the difference between sobriety and impairment, said Dr. Charles S.

Lieber, medical director of the Alcohol Research and Treatment Center at the Bronx center, who was

co-author of the report with Dr. Risto Roine. Did this study involve a simple random sample (SRS)? Explain.

Read the following brief article about aspirin and alcohol. Aspirin may enhance impairment by alcohol

Aspirin, a long time antidote for the side effects of drinking, may actually enhance alcohol’s effect,

researchers at the Bronx Veterans’ Affairs Medical Center say.

In a report on a study published in the Journal of the American Medical Association, the researchers

said they found that aspirin significantly lowered the body’s ability to break down alcohol in the

stomach.

As a result, five volunteers who had a standard breakfast and two extra-strength aspirin tablets an

hour before drinking had blood alcohol levels 30 percent higher than when they drank alcohol alone.

Each volunteer consumed the equivalent of a glass and a half of wine.

That 30 percent could make the difference between sobriety and impairment, said Dr. Charles S.

Lieber, medical director of the Alcohol Research and Treatment Center at the Bronx center, who was

co-author of the report with Dr. Risto Roine. Did this study use a particular design that we have studied? If so, identify the design. Then

comment on the validity of the study.

Bias is present in each of the following two sampling designs. In each case, identify the type of

bias involved and state whether you think the sample result obtained is lower or higher than the

actual population parameter. A political pollster seeks information about the proportion of American adults who oppose gun

controls. He asks an SRS of 1000 American adults: “Do you agree or disagree with the

following statement: Americans should preserve their constitutional right to keep and bear

arms.” A total of 910, or 91%, said, “Agree” (that is, 910 out of the 1000 oppose gun controls).

Bias is present in each of the following two sampling designs. In each case, identify the type of

bias involved and state whether you think the sample result obtained is lower or higher than the

actual population parameter. A flour company in Minneapolis wants to know what percent of local households bake at least

twice a week. A company representative calls 500 households during the daytime and finds

that 50% of them bake at least twice a week.

High blood pressure adds to the workload of the heart and arteries and may increase the risk of

heart attacks. If not treated, this condition can also lead to heart failure, kidney failure, or stroke.

Angiotensin-converting enzyme (ACE) inhibitors are used to treat high blood pressure. It is well

known that men and women may react differently to common cardiovascular drug treatments.

Most studies of heart drugs involved only a very small percent of women, and it was simply

assumed that the drug would work the same in both sexes. We want to conduct an experiment to

see if ACE inhibitors are less effective in women than in men. What sort of experimental design would you choose for this study, and why?

High blood pressure adds to the workload of the heart and arteries and may increase the risk of

heart attacks. If not treated, this condition can also lead to heart failure, kidney failure, or stroke.

Angiotensin-converting enzyme (ACE) inhibitors are used to treat high blood pressure. It is well

known that men and women may react differently to common cardiovascular drug treatments.

Most studies of heart drugs involved only a very small percent of women, and it was simply

assumed that the drug would work the same in both sexes. We want to conduct an experiment to

see if ACE inhibitors are less effective in women than in men. Use line 134 of the random digits table (below) to select the first 3 men for the study, and use

line 142 to select the first 3 women for the study.

134 27816 78416 18329 21337 35213 37741 04312 68508

142 72829 50232 97892 63408 77919 44575 24870 04178

First three men: 278, 167, 329

First three women: 295, 023, 297