Suppose that, prior to performing the clerical tasks in the experiment of Exercise 3, the first six participants took pills they thought to be caffeine but that were actually placebos; the remaining six participants ingested real caffeine pills.

a. Reanalyze the data in Exercise 3 as a mixed-design ANOVA, adding drug condition (placebo versus caffeine) as the between-groups variable. Test each F ratio for significance at the .05 level.

b. Compare the SS components you found as part of your analysis in part (a) to the SS components you found in Exercise 3. Which SS components are the same, and which combinations of SSs in part (a) add up to one of the SS components in Exercise 3?

c. Compute separate one-way RM ANOVAs for the placebo and the caffeine participants, and test these simple main effects for significance at the .05 level. How do these tests relate to your analysis in part (a)?

d. If this design was completely counterbalanced for each of the two drug groups, how many participants would have been assigned to each possible treatment order within each group?