Question: The Harrington Corporation manufactures DVDs. Tom Roberts, production manager, has a choice of the three subcontractors from which to buy parts. Tom purchases five batches from each subcontractor, with the same number of items in each batch. The number of detectives per batch is determined, and an analysis of variance is run on the computer. The results are partially summarized below:

Source of Variation SS df MSE F ratio
Between groups 496.54
Within groups 333.20 __
Total 14

a. State the null and alternative hypotheses.
b. Compute the appropriate degrees of freedom values.
c. State the decision rule if the null hypothesis is tested at the 0.01 significance level.
d. Complete the ANOVA table.
e. What should Tom conclude?