Scores for a common standardized college aptitude test are normally distributed
ID: 3044319 • Letter: S
Question
Scores for a common standardized college aptitude test are normally distributed with a mean of 498 and a standard deviation of 100. Randomly selected men are given a Test Preparation Course before taking this test. Assume, for sake of argument, that the preparation course has no effect.
If 1 of the men is randomly selected, find the probability that his score is at least 524.8.
P(X > 524.8) =
Enter your answer as a number accurate to 4 decimal places.
If 20 of the men are randomly selected, find the probability that their mean score is at least 524.8.
P(M > 524.8) =
Enter your answer as a number accurate to 4 decimal places.
Assume that any probability less than 5% is sufficient evidence to conclude that the preparation course does help men do better. If the random sample of 20 men does result in a mean score of 524.8, is there strong evidence to support the claim that the course is actually effective?
No. The probability indicates that it is too possible by chance alone to randomly select a group of students with a mean as high as 524.8.
Yes. The probability indicates that it is (highly ?) unlikely that by chance, a randomly selected group of students would get a mean as high as 524.8.
Explanation / Answer
a)
probability that his score is at least 524.8
2)
probability that their mean score is at least 524.8
3)as probability is higher than 0.05 level
No. The probability indicates that it is too possible by chance alone to randomly select a group of students with a mean as high as 524.8.
524.8 for normal distribution z score =(X-)/ here mean= = 498.000 std deviation == 100Related Questions
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