12.37 Two contrasts of interest for the stimulant study. Refer to Exercise 12.23 (page 669). There are two comparisons of interest to the experimenter. They are (1) placebo versus the average of the two low-dose treatments and (2) the difference between High A and Low A versus the difference between High B and Low B.

  1. (a) Express each contrast in terms of the means (μ’s) of the treatments.

  2. (b) Give estimates with standard errors for each of the contrasts.

  3. (c) Perform the significance tests for the contrasts. Summarize the results of your tests and your conclusions.