8. Reducing Hostility A psychologist wants to compare three methods for reducing hostility levels in university students. Eleven students were judged to have “great hostility,” based on a certain psychological test (HLT). These students were then randomly divided into three groups—five were treated by method A, three were treated by method B, and the other three students were treated by method C. All treatments continued throughout a semester, at the end of which the HLT test was given again. The results are shown in the table.

a. Perform an analysis of variance for this experiment.

b. Do the data provide sufficient evidence to indicate a difference in mean student scores after treatment for the three methods?

Method Scores on the HLT Test ABC A 73 83 76 68 80 54 74 71 79 95 87