The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find that the mean of this sample exceeds 104?
A) 0.0294
B) 0.9412
C) Approximately one
D) 0.9706

Question

Quizplus · Accepted Answer

The probability of selecting a sample of 50 adults and finding that the mean of this sample exceeds 104 is 0.0294. This is because the mean of a sample of 50 adults is normally distributed with a mean of 100 and a standard deviation of 15/sqrt(50) = 2.1213. The probability of selecting a sample with a mean greater than 104 is the area under the normal curve to the right of 104, which is 0.0294.

The Intelligence Quotient (IQ) Test Scores for Adults Are Normally