Question 918827: A professor wants to know what proportion of students earned an 'A' (score at least a 93) in a section from many years ago, but all he still has recorded is the mean and standard deviation. If the mean was 80 and the standard deviation was 7.9, what can you say about the proportion x of students who earned a score of at least 93?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A professor wants to know what proportion of students earned an 'A' (score at least a 93) in a section from many years ago, but all he still has recorded is the mean and standard deviation. If the mean was 80 and the standard deviation was 7.9, what can you say about the proportion x of students who earned a score of at least 93?
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z(93) = (93-80)/7.9 = 0.1625
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Ans: Prop >= 93 = P(z >= 0.1625) = normalcdf(0.1625,100) = 0.4355
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Cheers,
Stan H.
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