Question

For each of the problems below, list the type of test that is appropriate and describe why it is appropriate. (4 points each)

Clearly label each answer!

a. A researcher thinks that smoking cigarettes causes headaches. He measures whether 50 smokers have headaches prior to smoking cigarettes. He then has all the subjects smoke 2 cigarettes then measures the degree to which 50 smokers have headaches.

b. A researcher wants to know if people with larger heads are smarter. He collects IQ scores for 50 people with small heads and IQ scores for 50 people with large heads.

c. A psychology researcher randomly assigns a group of 50 high school students to receive a new assertiveness training program and 45 other high school students to receive the standard after-school program that focuses on social skills. She later measures how well each group performs on a measure of interpersonal assertiveness.

d. A researcher is interested in how family size influences social interaction. She has 12 subjects from very small families, 10 subjects from small families, 12 subjects from medium families, and 14 subjects from large families take a test on introversions.

Answer 1

a. A researcher thinks that smoking cigarettes causes headaches. He measures whether 50 smokers have headaches prior to smoking cigarettes. He then has all the subjects smoke 2 cigarettes then measures the degree to which 50 smokers have headaches.

We shall use a paired t-test to assess whether smoking cigarettes causes headaches. Her, since the measurements(number of headaches prior to smoking and after 2 cigarettes), the observations are paired and hence, a paired t-test is appropriate here.

b. A researcher wants to know if people with larger heads are smarter. He collects IQ scores for 50 people with small heads and IQ scores for 50 people with large heads.

We shall use an independent two-sample t-test. Here, the two groups are individuals are 50 with small heads and 50 with large heads. Hence the two groups are unrelated.

c. A psychology researcher randomly assigns a group of 50 high school students to receive a new assertiveness training program and 45 other high school students to receive the standard after-school program that focuses on social skills. She later measures how well each group performs on a measure of interpersonal assertiveness.

There are two groups of students one group(n=50) assigned to a new assertiveness program and the other group of 45 assigned to receive the standard after-school prgram. It is a two independent sample t-test.

d. A researcher is interested in how family size influences social interaction. She has 12 subjects from very small families, 10 subjects from small families, 12 subjects from medium families, and 14 subjects from large families take a test on introversions.

We have 4 groups of subjects who were subjected to a test on introversions. We shall be using an one way ANOVA test since there are more than two group involved.