Question

The manager of a computer software company wishes to study the number of hours per week senior executives by type of industry spend at their desktop computers. The manager selected a sample of five executives from each of three industries. At the 0.05 significance level, can she conclude there is a difference in the mean number of hours spent per week by industry?

Banking	Retail	Insurance
32	28	30
30	28	28
30	26	26
32	28	28
30	30	30
Complete the ANOVA table. Source SS df MS F Treatments Error

Answer 1

Following table shows the groups totals:

	Banking, G1	Retail, G2	Insurance, G3
	32	28	30
	30	28	28
	30	26	26
	32	28	28
	30	30	30
Total	154	140	142

Following table shows the grand total and sum of squares of values:

	G	G^2
	32	1024
	30	900
	30	900
	32	1024
	30	900
	28	784
	28	784
	26	676
	28	784
	30	900
	30	900
	28	784
	26	676
	28	784
	30	900
Total	436	12720

Conclusion: There is evidence, at the 0.05 significance level, that there is a difference in the mean number of hours spent per week by industry.