Independent random samples of six assistant professors, four associate professors, and five full professors were asked to estimate the amount of time outside the classroom spent. on teaching responsibilities in the last week. Results, in hours, are shown in the accompa- nying table. ASSISTANT ASSOCIATE FULL 7 15 11 12 12 7 11 15 6 15 9 8 9 7 14

(a) Set out the analysis of variance table.

(b) Test the null hypothesis that the three population mean times are equal.