document.write( "Question 885300: The scores on a statistics test were normally distributed with a mean of 78 and a standard deviation of 7.6. A student who took the test was randomly selected. What is the probability that the student scored higher than 85? \n" ); document.write( "

Algebra.Com's Answer #535061 by Theo(13342) $\"\"$ $\"About$

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mean = 78
\n" ); document.write( "standard deviation = 7.6
\n" ); document.write( "with a score of 85, the z score would be:
\n" ); document.write( "(85 - 78) / 7.6 = .92
\n" ); document.write( "from the z-score table, a z score of .92 will have .8212 of the area under the distribution curve to the left of it.
\n" ); document.write( "this means that a z score of .92 will have 100 - .8212 = .1788 of the area under the distribution curve to the right it it.
\n" ); document.write( "this means that the probability that the student scored higher than 85 is .1788.
\n" ); document.write( "the z-score table i used is shown below:
\n" ); document.write( "http://lilt.ilstu.edu/dasacke/eco148/ztable.htm
\n" ); document.write( "the z score was rounded to 2 decimal places to conform to the capabilities of the z score table.\r
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