Question

Scores for a common standardized college aptitude test are normally distributed with a mean of 490 and a standard deviation of 103. Randomly selected men are given a Test Preparation Course before taking this test. Assume, for sake of argument, that the test has no effect.

If 1 of the men is randomly selected, find the probability that his score is at least 528.7. P(X > 528.7) = Enter your answer as a number accurate to 4 decimal places.

If 12 of the men are randomly selected, find the probability that their mean score is at least 528.7. P(M > 528.7) = Enter your answer as a number accurate to 4 decimal places.

If the random sample of 12 men does result in a mean score of 528.7, is there strong evidence to support the claim that the course is actually effective?

Yes. The probability indicates that is is unlikely that by chance, a randomly selected group of students would get a mean as high as 528.7.

or

No. The probability indicates that is is possible by chance alone to randomly select a group of students with a mean as high as 528.7.

Answer 1