13.8 Using makeup. A study was performed in which 44 women participated as models. Each model was photographed after applying makeup as if she were going on a “night out.” Software was then used to create a sequence of 21 images ranging from 50% makeup to 150% makeup. Another set of observers (consisting of both sexes) was asked to look at each sequence of images and select the image that they felt was most attractive, what they felt was most attractive to other women, and what they felt was most attractive to other men. The average percent makeup over the 44 models was the response.

FIGURE 13.4 replicates one of the plots used in their summary.

a. Does there appear to be interaction between the sex of the observer and attractiveness category?

Explain your answer.

b. Describe what you see in terms of the main effects, making sure to relate these means to 100%

(the value that represents what the models applied themselves).

9 FIGURE 13.4 Interaction plot, Exercise 13.8.

Description The graph plots percent of makeup on the vertical axis, ranging from 60 to 85 in increments of 5, versus sex on the horizontal axis, labeled female and male. The graph has three parallel plots. A plot for attractive to men falls from (Female, 83) to (Male, 81). A plot for attractive to self falls from (Female, 75) to (Male, 73). A plot for attractive to women falls from (Female, 67) to

(Male, 64). All values estimated.