Forty-five percent of primary care doctors think their patients receive unnecessary medical care. If required, round your answer to four decimal places. (a) Suppose a sample of 300 primary care doctors was taken. Calculate the mean and standad deviation of the sample proportion of doctors who think their patients receive unnecessary medical care. np = 135 n(1-p) = 165 E( p ) = X (b) Suppose a sample of 500 primary care doctors was taken. Calculate the mean and standard deviation of the sample proportion of doctors who think their patients receive unnecessary medical care. np = 225 n(1-p) = 275 E( p ) = X X Of = (c) Suppose a sample of 1,000 primary care doctors was taken. Calculate the mean and standard deviation of the sample proportion of doctors who think their patients receive unnecessary medical care np = 450 0 n(1-p) = 550 X E( p ) = X Of = (d) In which of the preceding three cases, part (a) or part (b) or part (c), is the standard error of p smallest? Why? The standard error is the smallest in part (b) because p is the same in parts (a), (b), and (c) and the sample size is largest in part (b) x