Two tutoring services offer crash courses in preparation for the C.P.A. exam. To check on the effectiveness of these services, fifteen students were chosen. Five students were ran- domly assigned to service A, five were assigned to service B, and the remaining five took no crash course. Their scores on the examination, expressed as percentages, are given in the table. SERVICE A COURSE SERVICE B COURSE NO COURSE 22869 79 74 67 85 23 = 3 74 72 69 71 87 81 81 61 64 63

(a) Set out the analysis of variance table.

(b) Test the null hypothesis that the three population mean scores are the same.