Scores for a common standardized college aptitude test are normally distributed with a mean of 510 and a standard deviation of 115. Randomly selected men are given a Preparation Course before taking this test. Assume, for sake of argument, that the Preparation Course has no effect on people's test scores. If 1 of the men is randomly selected, find the probability that his score is at least 562.9. P(X > 562.9) =
Scores for a common standardized college aptitude test are
If 1 of the men is randomly selected, find the probability that his score is at least 562.9.
P(X > 562.9) =
Enter your answer as a number accurate to 4 decimal places.
If 8 of the men are randomly selected, find the probability that their mean score is at least 562.9.
P(x-bar > 562.9) =
Enter your answer as a number accurate to 4 decimal places.
If the random sample of 8 men does result in a mean score of 562.9, is there strong evidence to support a claim that the Preparation Course is actually effective? (Use the criteria that "unusual" events have a probability of less than 5%.)
- Yes. The probability indicates that is highly unlikely that by chance, a randomly selected group of students would get a mean as high as 562.9 if the Preparation Course has no effect.
or
- No. The probability indicates that is possible by chance alone to randomly select a group of students with a mean as high as 562.9 if the Preparation Course has no effect.
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