SOLUTION: If X is a normal random variable with a mean of 4, and if the probability that X is less than 5.76 is .72, then what is the standard deviation of X?

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Question 429430: If X is a normal random variable with a mean of 4, and if the probability that X is less than 5.76 is .72, then what is the standard deviation of X?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
mu+=+4
==> P%28X+%3C+5.76%29+=+0.72
==> P%28%28X+-+4%29%2Fsigma+%3C+1.76%2Fsigma%29+=+0.72
==> 1.76%2Fsigma+=+0.58, approximately.
==> sigma+=+3.0345, to 4 decimal places.