7.3 House owners in a district In order to estimate the proportion p of people who own houses in a district, we choose a random sample from the population and study its sampling distribution. Assuming p = 0.3, use the appropriate formulas from this section to find the mean and the standard deviation of the sampling distribution of the sample proportion for a random sample of size:

a. n = 400.

b. n = 1600.

c. n = 100.

d. Summarize the effect of the sample size on the size of the standard deviation.