document.write( "Question 1174137: A child psychologist wants to estimate the mean age at which a child learns to talk using a confidence interval. Find the sample size necessary for a 99% confidence interval with maximum error estimate of 4 weeks for the mean age at which a child learns to talk. Assume σ = 25 weeks. \n" ); document.write( "

Algebra.Com's Answer #799536 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi,\r\n" );
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document.write( "Normal Distribution:  σ = 25 and ME = 4 \r\n" );
document.write( "Find the sample size necessary for a 99% confidence interval \r\n" );
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document.write( " ME =\r\n" );
document.write( "Or\r\n" );
document.write( "  n =  \r\n" );
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document.write( "  n =  = 16.1  0r  17 rounded up (to be on the safe side)\r\n" );
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document.write( "   17 the sample size necessary for a 99% confidence interval \r\n" );
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document.write( " = CI	z = value\r\n" );
document.write( "90%	z =1.645\r\n" );
document.write( "92%	z = 1.751\r\n" );
document.write( "95%	z = 1.96\r\n" );
document.write( "98%	z = 2.326\r\n" );
document.write( "99%	z = 2.576\r\n" );
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document.write( "Wish You the Best in your Studies.\r\n" );
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