Sleep duration data (in hours/ night) are shown for the patients of Exercise 18.13.

Sequence 1 received the investigational drug first and the placebo second; the reverse order applied to sequence 2.
a. Compute means and standard errors per sequence per period.
b. Plot these data to show what happened during the study. Does the investigational drug appear to affect sleep duration? In what way? Use a 5.05.
c. Run a repeated measures analysis of variance for this design. Draw conclusions. Does the analysis of variance confirm your impressions in part (b)?

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