Eyewitnesses and mug shots. Refer to the Applied Psychology in Criminal Justice (Apr. 2010) study of mug shot choices by eyewitnesses to a crime, Exercise 10.107

(p. 598). Recall that a sample of 96 college students was shown a video of a simulated theft, then asked to select the mug shot that most closely resembled the thief. The students were randomly assigned to view either 3, 6, or 12 mug shots at a time, with 32 students in each group. The number of students in the 3-, 6-, or 12-photos-per-page groups who selected the target mugshot were 19, 19, and 15, respectively.

a. For each photo group, compute the proportion of students who selected the target mug shot. Which group yielded the lowest proportion?

b. Create a contingency table for these data, with photo group in the rows and whether or not the target mug shot was selected in the columns.

c. Refer to part

b. Are there differences in the proportions who selected the target mug shot among the three photo groups? Test, using a = .10.