Answer:
The values of n, p and q are 314, 0.12 and 0.88 respectively.
Explanation:
n is the number of subjects given a placebo. The value of n is 314.
p is the sample proportion of the subjects given a placebo that developed headaches. The value of is 12% = 0.12
q is the sample proportion of the subjects given a placebo that did not develop headaches. The value of q = 1 - p = 1 - 0.12 = 0.88