Chapter 12.2, Problem 1AC

Colors That Make You Smarter

The following set of data values was obtained from a study of people’s perceptions on whether the color of a person’s clothing is related to how intelligent the person looks The subjects rated the person’s intelligence on a scale of 1 to 10 Randomly selected group 1 subjects were shown people with clothing in shades of blue and gray. Randomly selected group 2 subjects were shown people with clothing in shades of brown and yellow. Randomly selected group 3 subjects were shown people with clothing m shades of pink and orange. The results follow.

Group 1	Group 2	Group 3
8	7	4
7	8	9
7	7	6
7	7	7
8	5	9
8	8	8
6	5	5
8	8	8
8	7	7
7	6	5
7	6	4
8	6	5
8	6	4

1. Use the Tukey test to test all possible pairwise comparisons.

2. Are there any contradictions in the results?

3. Explain why separate t tests are not accepted in this situation.

4. When would Tukey’s test be preferred over the Scheffé method? Explain