The operations manager for an appliance manufacturer wants to determine the optimal length of time for the washing cycle of a household clothes washer. An experiment is designed to measure the effect of detergent brand and washing cycle time on the amount of dirt removed from standard houschold laundry loads. Four brands of detergent (A, B.CD) and four levels of washing cycles (18, 20, 22, and 24 minutes) are specifically selected for analysis. 32 standard household laundry loads (having equal weight and dirt) are randomly assigned to the 16 detergent-washing cycle time combinations.

The results (in pounds of dirt removed) are: Washing Cycle Time (in Minutes) Brand 0.11 0.09 0.12 0.1 0.08 0.09 0.11 20 0.13 0.13 0.14 0.15 0.16 0.13 0.12 0.13 0.17 0.19 0.17 0.18 0.18 24 0.17 0.18 0.19 0.17 0.2 0.16 0.15 0.16 0.17

Perform a Two-way Analysis of Variance with Replication in Excel and output the ANOVA table assuming a 5% level of significance. which washing cycle times do NOT show a significant different results (at alpha = 0.05 in the pounds of dart removed? Perform the appropriate multiple comparisons procedure by hand to determine the result.

a. 22 and 24 minutes

b. 18 and 20 minutes

c. 20 and 24 minutes

d. 18 and 24 minutes