In each ofthe following cases, nd the mean, variance, and standard deviation of the sampling distribution ofthe sample proportion 3?. {a) p = .6, n = 258 {Round variance to 6 decimal places and standard deviation to 4 decimal places. Do not round intermediate values.) {b) p = .3, n =116 {Round variance to 6 decimal places and standard deviation to 4 decimal places. Do not round intermediate values.) {c) p = .6, n = 418 {Round variance to 6 decimal places and standard deviation to 4 decimal places. Do not round intermediate values.) {d} p = .85, n = 971 {Round variance to 6 decimal places and standard deviation to 4 decimal places. Do not round intermediate values.)