SOLUTION: Assume that IQ scores are normally distributed, with a standard deviation of 18 points and a mean of 100 points. If 85 people are chosen at random, what is the probability that the

Algebra ->  Probability-and-statistics -> SOLUTION: Assume that IQ scores are normally distributed, with a standard deviation of 18 points and a mean of 100 points. If 85 people are chosen at random, what is the probability that the      Log On


   

Question 1076029: Assume that IQ scores are normally distributed, with a standard deviation of 18 points and a mean of 100 points. If 85 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.)
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Standard error of mean is sigma/sqrt(n)=18/sqrt (85)=1.95
z (lower) is (98-100)/1.95=-2/1.95=-1.024
z (upper) is +1.024
Want probability in between, which is 0.6943.