Assume that IQ scores are normally distributed, with a standard deviation of 11 points and a mean of 100 points. If 150 people are chosen at random, what is the probability that the sample mean of IQ scores will not differ from the population mean by more than 2 points? (Round your answer to four decimal places.) Solution s=11 u=100 n=150 let sample mean be \'x\' x-u = +/- 2 x-100 = +/- 2 x1=98 x2=102 z1 = (x1-u) / (s/sqrt(n)) = -2.23 z2 = 2.23 P(98.