The manager of a computer software company is studying the number of hours too executives spend at their desktop computers by type of industry. A random sample of 4 executives from each if three industries is obtained, and the results are presented in the following table. Banking: 12,10,10,12. Retail: 8,8,6,10. Insurance: 9,8,9,8.
Assume the samples come from normal populations with equal variances. At the 5% significance level, test the hypothesis that there is no difference in the mean weekly hours that executives in the three industries spend at their desktop computers.
Formulate and test the appropriate hypothesis. Use the critical value approach. Assume SSB= 20.6667 and SSW= 13.