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 Figure 11.8, along with the Excel output of a randomized block ANOVA of these data. Using the computer output:

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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ANOVA: Two-Factor without Replication Salesman,J Sales Method,A 32 32 28 25 29 30 25 24 C SUMMARY Count 30 Method 1 28 Method 2 23 Method 3 23 Method 4 Sum Average Varlance 30.3333 2.3333 4 6.3333 91 90 76 72 30 25.3333 24 29.25 27 26 Salesman A Salesman B Salesman C 108 104 11.5833 8.6667 12.6667 4 ANOVA Source of Variation Ss df Rows Columns Error Total MS 3 31.1944 36.2258 2 11.0833 12.8710 P-value F crit 71 0.0068 5.1433 93.5833 22.1667 5.1667 120.9167 0.0003 4.75 0.8611