Arandom sample of n = 64 observations is drawn from a population with a mean equal to 20 and standard deviation equal to 16. (give answers to four decimal places.) a) give the mean and standard deviation of the (repeated) sampling distribution of x. mean = standard deviation = b) calculate the standard normal z-score corresponding to a value of x = 16. c) calculate the standard normal z-score corresponding to a value of x = 23. d) find p(x < 16). e) find p(x > 23). f) find p(16 < x < 23).