Given:
p = 0.15
The mean and standard deviation(S.D) can be calculated using the formula:
(a) A random sample of size n = 4000
mean = 0.14
SD:
SD = 0.005486
(b) A random sample of size n = 1000
mean = 0.14
SD:
SD = 0.01097
(C) A random sample of size n = 250
mean = 0.14
SD:
SD = 0.02195