document.write( "Question 1207011: The maintenance department at the main campus of a large state university receives daily requests to replace fluorescent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 64 and a standard deviation of 9. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 64 and 82? \n" ); document.write( "

Algebra.Com's Answer #844806 by ikleyn(52794) $\"\"$ $\"About$

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\n" ); document.write( "The maintenance department at the main campus of a large state university
\n" ); document.write( "receives daily requests to replace fluorescent lightbulbs.
\n" ); document.write( "The distribution of the number of daily requests is bell-shaped
\n" ); document.write( "and has a mean of 64 and a standard deviation of 9.
\n" ); document.write( "Using the 68-95-99.7 rule, what is the approximate percentage
\n" ); document.write( "of lightbulb replacement requests numbering between 64 and 82?
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document.write( "Notice that in this problem 82 is two standard deviation up from the mean of 64. \r\n" );
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document.write( "Since the normal distribution is symmetric, we may conclude that approximate percentage \r\n" );
document.write( "of lightbulb replacement requests numbering between 64 and 82 is half of 95%-50%, i.e. \r\n" );
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document.write( "     = 22.5%.    ANSWER\r\n" );
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