Question

Be sure to complete each problem in the Hypothesis format and show all work for solution.

Assumptions underlying the repeated-measures t test.

Individuals with a condition known as "prosopagnosia" cannot recognize faces. Their perceptual abilities are intact, and they can accurately describe feature such as eye color, size of the nose, and shape of the mouth. They can even tell you whether someone is attractive. However, they cannot recognize anyone's face, not even the faces of their friends and family. Dr. Joseph DeGutis has been conducting research and trying to develop a training regimen that would allow patients with prosopagnosia to improve their recognition abilities. Patients complete a battery of perceptual tests to determine their baseline performance (a pre-test) and then are trained for 6 days on a facial categorization task. They are tested again (a post-test) to determine their levels of improvement.

Would it be valid for Dr. DeGutis to use the independent-measure t test to test whether the training leads to an improvement?

A. Yes.

B. No, because he does not have homogeneity of variance.

C. No, because Dr. DeGutis is using a repeated-measures (within-subjects) research design. In this type of design, the study populations are not independent.

D. Yes, if his sample size is less than or equal to 30 or the raw scores are normally distributed.

Answer 1

No, because Dr. DeGutis is using a repeated-measures (within-subjects) research design. In this type of design, the study populations are not independent.

Option C is correct.