A marketing organization wishes to study the effects of four sales methods on weekly sales of a product. The organization employs a randomized block design in which three salesman use each sales method. The results obtained are given in Table 11.9. Figure 11.8 gives the Excel output of a randomized block ANOVA of the sales method data.
TABLE 11.9
Results of a Sales Method Experiment Employing a Randomized Block Design

FIGURE 11.8
Excel Output of a Randomized Block ANOVA of the Sales Method Data Given in Table 11.9

a. Test the null hypothesis H0 that no differences exist between the effects of the sales methods (treatments) on mean weekly sales. Set α = .05. Can we conclude that the different sales methods have different effects on mean weekly sales?
b. Test the null hypothesis H0 that no differences exist between the effects of the salesmen (blocks) on mean weekly sales. Set α = .05. Can we conclude that the different salesmen have different effects on mean weekly sales?
c. Use Tukey simultaneous 95 percent confidence intervals to make pairwise comparisons of the sales method effects on mean weekly sales. Which sales method(s) maximize mean weekly sales?

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Salesman, j 32 Sales Method, i A 32 32 28 25 32 29 30 25 24 28 23 23 28 R 27 29 a) 28 25 24 23 R 27 26 25 24 23 2 Method 3 Salespersorn ANOVA: Two-Factor without Replication SUMMARY Method 1 Method 2 Method 3 Method 4 Salesman A Salesman B Salesman C Sum 91 90 76 72 Variance 2.3333 4 6.3333 Count Average 30.3333 30 25.3333 24 29.25 27 26 4 11.5833 8.6667 12.6667 104 ANOVA Source of Variation Rows Columns Error Total MS 31.1944 11.0833 0.8611 P-value 0.0003 0.0068 F crit 4.7571 5.1433 df 93.5833 22.1667 5.1667 120.9167 36.2258 12.8710