Consider Example 11.2, and let B, M and r represent the mean monthly sales when using the bottom, middle, and top shelf display heights, respectively.

Consider Example 11.2, and let µB, µM and µr represent the mean monthly sales when using the bottom, middle, and top shelf display heights, respectively. Figure 11.3 gives the MINITAB output of a one-way ANOVA of the bakery sales study data in Table 11.2
FIGURE 11.3
MINITAB Output of a One-Way ANOVA of the Bakery Sales Study Data in Table 11.2

a. Test the null hypothesis that µB, µM and µr, are equal by setting α = .05. On the basis of this test, can we conclude that the bottom, middle, and top shelf display heights have different effects on mean monthly sales'?
b. Consider the pairwise differences µB, µM µr µB and µr - µM. Find a point estimate of and a Tukey simultaneous 95 percent confidence interval for each pairwise difference. Interpret the meaning of each interval in practical terms. Which display height maximizes mean sales?
c. Find an individual 95 percent confidence interval for each pairwise difference in part b. Interpret each interval.
d. Find 95 percent confidence intervals for µB, µM and µr. Interpret each interval.

One-way ANOVA: Bakery sales versus Display Height Source Diaplay Height 2 2273.88 1136.94 184.57 0.000 Tukey 95% Simultaneous DF Confidence Intervals Bottom subtracted fromt Middle 17.681 21 400 25.119 15 92.40 .16 rror Total 17 2366 28 Lower Center Upper Individual 95% CIa For Mean Based on Pooled StDev Level N Mean StDev- Bottom 6 55.800 2.477 Middle 677.200 3.103 Top Top .019 300 0.581 Middle #ubtracted from: Top -29.419 25 700 21.981 Lower Center Upper 6 51.500 1.648 (*--) Pooled BtDev 2.482 56.0 64.0 72.0 80.0