An aptitude test has a mean score of 80 and a standard deviation of 5. The population of scores is normally distributed. What proportion of tests has scores over 90?
A) .9772
B) .0228
C) .9544
D) .0456

Name: An aptitude test has a mean score of 80 and a standard deviation of 5. The population of scores is normally distributed. What proportion of tests has scores over 90? A) .9772 B) .0228 C) .9544 D) .0456
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Question

Quizplus · Accepted Answer

z = (90 − 80)/5 = 2
p(X > 90) = 1 − .9772 = .0228

An Aptitude Test Has a Mean Score of 80 and a Standard