SOLUTION: Scores on a test have a mean of 73 and 10 percent of the scores are above 87. The scores have a distribution that is approximately normal. Find the standard deviation.

SOLUTION: Scores on a test have a mean of 73 and 10 percent of the scores are above 87. The scores have a distribution that is approximately normal. Find the standard deviation.

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Question 800697: Scores on a test have a mean of 73 and 10 percent of the scores are above 87. The scores have a distribution that is approximately normal. Find the standard deviation.
Answer by oscargut(2103) (Show Source): You can put this solution on YOUR website!

P(X>87)=0.1
P(Z> (87-73)/s ) = 0.1
14/s = 1.28
s = 14/1.28
s = 10.94
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