34. For the treatment of anxiety and tension, Sainsbury and Lucas ( Sequential Methods Applied to the Study of Prochlorperazine, British Med. J., 1959:

737—740) conducted an experiment to see if prochlorperazine was effective. The design was similar to the one used in Example 14.9, with both the drug and a placebo being taken by each patient in random order double-blind; that is, neither the patient nor the physician knew which treatment was being given while the treatments were being evaluated.

Each subject was asked which treatment was preferred, so the result is a Bernoulli rv. For this experiment p0  .5, p1  .8, a  .05, b  .05.

a. Determine the linear boundaries such that the experiment continues if the number of successes remains within the lines.

b. Given the data S, S, F, F, F, F, S, S, F, S, S, F, S, F, F determine the result of the experiment.

c. Find the expected number of observations needed under H0 and under Ha.

d. Find the number of trials needed if the experiment were conducted with a xed sample. Compare with the answer to part

(c) and the number actually used.