In a study of 10 new producers of iron supplements, nine contrasts in the mean iron level in the supplements were constructed by the quality control department for comparing various characteristics of the producers.

a. In order to achieve an experimentwise error rate or .05, what value should be selected for the value ai?

b. What is the critical value for the F statistic for testing the nine contrasts if there were six samples of the supplement taken from each of the ten producers?