8.21 Suppose that we will randomly select a sample of n = 100 elements from a population and that we will compute the sample proportion p of these elements that fall into a category of interest. If the true population proportion p equals .9: a Describe the shape of the sampling distribution of p. Why can we validly describe the shape? b Find the mean and the standard deviation of the sampling distribution of p. c Find P(p 2 .96). d Find P(.855