document.write( "Question 887937: How large a sample size is needed to estimate the mean annual income of people in a certain country, correct to within $800 with probability 0.99? No information is available about the standard deviation of their income. It is estimated that nearly all of the incomes fall between $0 and $180,000 and that this distribution is approximately bell-shaped.\r
\n" ); document.write( "\n" ); document.write( "n =
\n" ); document.write( "(round up to the nearest integer) \n" ); document.write( "
Algebra.Com's Answer #536943 by stanbon(75887)\"\" \"About 
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How large a sample size is needed to estimate the mean annual income of people in a certain country, correct to within $800 with probability 0.99? No information is available about the standard deviation of their income. It is estimated that nearly all of the incomes fall between $0 and $180,000 and that this distribution is approximately bell-shaped.
\n" ); document.write( " n =[z*s/E]^2
\n" ); document.write( "Comment: When sigma is not given 6*s = range of the data = 180,000
\n" ); document.write( "s = 180,000/6 = 30,000
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\n" ); document.write( "n = [2.5758*30,000/800]^2 = 9331 (rounded up to the nearest integer)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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