document.write( "Question 1112396: How large a sample should be taken if the population mean is to be estimated with 99% confidence to within $71? The population has a standard deviation of $892. (Round your answer up to the next whole number.) \n" ); document.write( "

Algebra.Com's Answer #727413 by Boreal(15235) $\"\"$ $\"About$

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the half interval is 71
\n" ); document.write( "99% CI is z(0.995) or 2.576
\n" ); document.write( "The half interval is z*sigma/sqrt(n)=71
\n" ); document.write( "2.576*892=71*sqrt(n), multiplying through
\n" ); document.write( "dividing by 71
\n" ); document.write( "sqrt (n)=32.36
\n" ); document.write( "square both sides
\n" ); document.write( "n=1047.38, round up to
\n" ); document.write( "n=1048 \n" ); document.write( "

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