document.write( "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? \n" ); document.write( "

Algebra.Com's Answer #298261 by robertb(5830) $\"\"$ $\"About$

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$\"mu+=+4\"$
\n" ); document.write( "==> $\"P%28X+%3C+5.76%29+=+0.72\"$
\n" ); document.write( "==> $\"P%28%28X+-+4%29%2Fsigma+%3C+1.76%2Fsigma%29+=+0.72\"$
\n" ); document.write( "==> $\"1.76%2Fsigma+=+0.58\"$ , approximately.
\n" ); document.write( "==> $\"sigma+=+3.0345\"$ , to 4 decimal places. \n" ); document.write( "

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