An experiment was conducted to compare the effectiveness of three training programs, A, B, and C, in training assemblers of a piece of electronic equipment. Fifteen employees were randomly assigned, five each, to the three programs. After completion of the program, each person was required to assemble four pieces of the equipment, and the average length of time required to complete the assembly was recorded. Several of the employees resigned during the course of the program; the remainder were evaluated, producing the data shown in the accompanying table. Use the Excel printout to answer the questions.

a. Do the data provide sufficient evidence to indicate a difference in mean assembly times for people trained by the three programs? Give the p-value for the test and interpret its value.
b. Find a 99% confidence interval for the difference in mean assembly times between persons trained by programs A and B.
c. Find a 99% confidence interval for the mean assembly times for persons trained by program A.
d. Do you think the data will satisfy (approximately) the assumption that they have been selected from normal populations? Why?
MS Excel output for Exercise 11.12

Training Program Average Assembly Time (min) 59 64 57 62 52 58 54 58 65 71 63 64 Anova: Single Factor SUMMARY Groups Count Sum Average Variance 9.667 3 164 54.667 9.333 5 32164.221.7 4 242 60.5 ANOVA Source of Variation SS Between Groups 170.45 285.225 5.704 0.0251 4.256 Within Groups Total df MS P-value F crit 134.467 9 14.941 304.917 11