Given data shows that mean of 200 and a standard deviation of 50. The probability that their mean is above 215 is calcualted by :
(215-200)/[50/sqrt(40)] = 1.8974
P(x-bar > 215) = P(z > 1.8974) = normalcdf(1.8974,100) = 0.0289.
if 40 different applicants are randomly​ selected, the probability that their mean is above 215 will be 0.0289.
