document.write( "Question 1002529: the distribution of IQ scores has a mean of 120 and a standard deviation of 8, use the theorem to determine the interval containing at least 8/9 of the IQ scores. At least what percentage of these scores must lie between 104 and 136 ? \n" ); document.write( "
Algebra.Com's Answer #619400 by stanbon(75887)\"\" \"About 
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the distribution of IQ scores has a mean of 120 and a standard deviation of 8, use the theorem to determine the interval containing at least 8/9 of the IQ scores.
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\n" ); document.write( "Chebyshev says \"at least 1-(1/n)^2 % of the data lies within n
\n" ); document.write( "standard deviations of the mean\".
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\n" ); document.write( "If 1-(1/n)^2 = 8/9, (1/n)^2 = (1/9) and n = 3
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\n" ); document.write( "The interval:
\n" ); document.write( "Lower bound:: 120-3*8 = 96
\n" ); document.write( "Upper bound:: 120+3*8 = 144
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\n" ); document.write( "At least what percentage of these scores must lie between 104 and 136 ?
\n" ); document.write( "104 = 120-8n
\n" ); document.write( "8n = 16
\n" ); document.write( "n = 2
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\n" ); document.write( "136 = 120+8n
\n" ); document.write( "8n = 16
\n" ); document.write( "n = 2
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\n" ); document.write( "Ans: % of data within 2 std of the mean = 1-(1/2)^2 = 0.75 = 75%
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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