Exam 13: Hypothesis Tests Applied to Means: Two Related Samples

Suppose that we take 15 gay couples and observe the difference within couples in terms of age. Then we take 15 straight couples are record the same differences. We want to test if straight couples are more similar in age than gay couples. (There is some reason to expect that this is true.) What statistical procedure would be most appropriate?

The mean of a column of difference scores is equal to

Repeated measures designs are subject to order effects.

A researcher hypothesized that adolescent girls are more invested in their romantic relationships than are adolescent boys. She asked adolescent partners to rate the total amount of time they engaged in activities centered around their relationship (e.g., seeing each other, thinking about the partner, talking about the relationship with others). In a sample of 41 couples, girls spent an average of 12 hours a week and boys an average of 10. The standard deviation of the difference was 1.5 hours. a. Calculate t . b. Was the research hypothesis supported? Explain.

The null hypothesis in a repeated measures t test is

In Chapter 13 the calculation for a repeated measures t test on change within subjects is given as Use this formula for the next several questions. In a repeated measures t , the degrees of freedom are equal to

Which of the following terms does NOT belong with the rest?

If we test the mean amount that alcoholic subjects drink before and after therapy, and that difference is NOT statistically significant, this could mean

The following is part of the printout from an SPSS analysis of data on paired samples.  Use it to answer the next several questions. The confidence limits in the output can best be interpreted to mean

When we have related samples, the best measure of the effect size uses

In a related samples t test, the difference score is usually compared to 0.

A kindergarten teacher wanted to see if her students' social skills changed over the academic year. She compared the scores on a standardized measure of social skills at the beginning of the year, and the end of the year. The results follow: a. What is the null hypothesis? b. Is a one or two-tailed test more appropriate? c. Calculate t . d. Write a sentence explaining the results.

In the Kaufman and Rock (1972) moon illusion example in the text, they hypothesized that there would be no moon illusion in their experiment. Experiments of this type pose problems for researchers because

A repeated measures t test would be appropriate to see if students who took the SAT in 2000 scored higher than students who took the SAT in 2002.

The example of the moon illusion discussed in the text illustrates the fact that

We would be least likely to use a repeated measures design when

In Chapter 13 the calculation for a repeated measures t test on change within subjects is given as Use this formula for the next several questions. If the critical value of t associated with the above formula is 2.12, what would you conclude about your means?

In repeated measures designs, the difference score refers to the difference in standard deviations for the two variables being compared.

Give an example in which carryover effects may impact a repeated measures design unduly.

In the t test for repeated measures the symbol S_D stands for the