Go directly to main content

Kathryn Holcomb

Practice with Experiments Homework

Due Monday, July 15

Worth 12 points

1. For each of the following research studies, explain why it is or is not an example of the experimental research strategy.

a. In a study examining the relationship between dietary fiber and cholesterol, a sample of 50-year-old men is randomly separated into two groups. Each group eats exactly the same diet for 2 months, except that one group also gets 2 cups of oatmeal every day. At the end of 2 months, the cholesterol level is measured for each man. The researcher hopes to find a difference between the two groups.

b. To evaluate the relationship between stress and general health, a researcher selects a random sample of 50-year-old men. For 2 months, each man is asked to keep a daily journal recording stressful events (such as a fight with his wife, an argument with his boss, or an automobile accident). After 2 months, a doctor examines each man and records an overall health rating. The goal of the study is to determine whether there is a relationship between the total amount of stress and overall health of the men.

c. In a study examining the relationship between self-esteem and dishonest behavior, college students were first given a self-esteem questionnaire to classify them into high and low self-esteem groups. At a later time, cheating behavior was measured while the students corrected this own exams. The goal of the study is to find a difference between the two groups.

d. A researcher conducts a study examining the relationship between viewing violent television and aggressive behavior of 5-year-old boys. A group of boys is randomly separated; half the boys are shown violent television programs for 30 minutes before play time and the other half of the boys are shown nonviolent television programs during the same period. Aggressive behavior is then measured by observing the children during an outdoor play period to determine if there is any difference between the two groups.

Read the following examples and answer the questions that follow them.

2. Dr. Jones conducts a research study investigating the effects of a new drug that is intended to reduce the craving for alcohol. A group of alcoholics who are being treated at a clinic is selected for the study. Half of the participants are randomly assigned to be given the drug along with their regular treatment, and the other half receives a placebo along with their regular treatment. Dr. Jones records whether each individual is still sober after 6 months.

a. Identify the independent variable in this study, and its levels (or what is happening at each level of the independent variable).

b. Identify the dependent variable in this study.

c. Assuming that the study includes participants ranging in age from 18 to 62 years of age, then which of the following most accurately describes the age variable in the study? (independent, dependent, extraneous, confounding)

d.   If the participants in the drug group are noticeably older (on average) than the individuals in the placebo group, then which of the following most accurately describes the age variable in the study? (independent, dependent, extraneous, confounding)

3. Dr. Cantu conducts an experiment investigating the effects of distraction on memory. A list of 40 two-syllable words is prepared. Dr. Cantu obtains a sample of 50 students, all between the ages of 18 and 22, and presents the list of words to the entire group. Then each individual is randomly assigned to one of two groups. One group of participants is given a memory test for the list of words in a quiet room, and the second group is tested in a room with loud construction noises (hammering, sawing, and so on) in the background.

a. Identify the independent variable in this study, and its levels (or what is happening at each level of the independent variable).

b. Identify the dependent variable in this study.

c. Explain why Dr. Cantu can be reasonably confident that the participants’ age is not a confounding variable. That is, explain why it is unlikely that one group will do better on the memory task because they are substantially older than the other group.

d.   Although personality varies from one participant to another, Dr. Cantu is probably not worried about personality as a confounding variable. Explain why not.

give online to IU Kokomo

What matters. Where it matters.

Privacy Notice