Scores for a common standardized college aptitude test are normally distributed with a mean of 500 and a standard deviation of 111. Randomly selected men are given a Test Prepartion Course before taking this test. Assume, for sake of argument, that the course has no effect. If 1 of the men is randomly selected, find the probability that his score is at least 554.5. P(xx > 554.5) = Enter your answer as a number accurate to 4 decimal places. If 15 of the men are randomly selected, find the probability that their mean score is at least 554.5. P(xx > 554.5) = Enter your answer as a number accurate to 4 decimal places. If the random sample of 15 men does result in a mean score of 554.5, 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 554.5.
• No. The probability indicates that is is possible by chance alone to randomly select a group of students with a mean as high as 554.5.