Eyewitnesses and mugshots. Refer to the Applied Psychology

Chapter 10, Problem 28E

(choose chapter or problem)

QUESTION:

Eyewitnesses and mugshots. Refer to the Applied Psychology in Criminal Justice (April 2010) study of mugshot choices by eyewitnesses to a crime, Exercise 9.78 (p. 547). Recall that a sample of 96 college students was shown a video of a simulated theft, then asked to select a mugshot that most closely resembled the thief. The students were randomly assigned to view either 3, 6, or 12 mugshots at a time, with 32 students in each group. The number of students in the 3-, 6-, and 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 mugshot. 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 mugshot was selected in the columns.

c. Analyze the contingency table, part b. Are there differences in the proportions who selected the target mugshot among the three photo groups? Test using $\alpha$ = .10.

Questions & Answers

QUESTION:

a. For each photo group, compute the proportion of students who selected the target mugshot. 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 mugshot was selected in the columns.

c. Analyze the contingency table, part b. Are there differences in the proportions who selected the target mugshot among the three photo groups? Test using $\alpha$ = .10.

ANSWER:

Step 1 of 10

(a)

The proportion of students in the 3-photos per page group who selected the target mugshot is denoted as , the proportion of students in the 6-photos per page group who selected the target mugshot is denoted as , the proportion of students in the 12-photos per page group who selected the target mugshot is denoted as .