Yeast. To shorten the time it takes him to make his favorite pizza, a student designed an experiment to test the effect of sugar and milk on the activation times for baking yeast. Specifically, he tested four different recipes and measured how many seconds it took for the same amount of dough to rise to the top of a bowl. He randomized the order of the recipes and replicated each treatment 4 times.

Here are the boxplots of activation times from the four recipes:

The ANOVA table follows:
Source DF Sum of Squares Mean Square F-Ratio P-Value Recipe 3 638967.69 212989 44.7392 60.0001 Error 12 57128.25 4761 Total 15 696095.94

a) State the hypotheses about the recipes (both numerically and in words).

b) Assuming that the assumptions for inference are satisfied, perform the hypothesis test and state your conclusion. Be sure to state it in terms of activation times and recipes.

c) Would it be appropriate to follow up this study with multiple comparisons to see which recipes differ in their mean activation times? Explain.