In an early study of the effects of frustration on feelings of hostility, Miller and Bugelski (1948) had a group of boys at a camp rate their attitudes toward two groups (Mexicans and Japanese). The campers then participated in a long, difficult, frustrating testing session that kept them away from their weekly movie. Finally the boys again rated their attitudes towards the minority groups. The scores below represent the number of unfavorable traits attributed to minorities and are similar to those of miller and Bugelski.

ParticipantBeforeAfter

A56

B44

C35

D34

E24

F23

G13

H02

a. Does the intervening unpleasant task alter attitudes toward the two groups? Use a two-tailed test with=.05.

b. Computer r², the percentage of variance accounted for, to measure effect size