document.write( "Question 1008328: Dear tutor, I have a hard time calculating the variance of the means. almost spent 3 hrs to figure this out. but still no luck.
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\n" ); document.write( "\n" ); document.write( "Q.The table shows the means and variances from 5 experimental conditions. Compute the variance of the means.
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\n" ); document.write( " 4.5 1.33
\n" ); document.write( " 7.2 0.98
\n" ); document.write( " 3.4 1.03
\n" ); document.write( " 9.1 0.78
\n" ); document.write( " 1.2 0.56\r
\n" ); document.write( "\n" ); document.write( "What I did was I added all the variance and divided by (1/25) but I do not get the answer 9.717\r
\n" ); document.write( "\n" ); document.write( "ANSWER : 9.717\r
\n" ); document.write( "\n" ); document.write( "Thank you in advance! \n" ); document.write( "
Algebra.Com's Answer #624076 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Follow directions. You are told to compute the variance of the means.\r\n" );
document.write( "So you don't pay any attention to those individual variances.\r\n" );
document.write( "You look at the 5 means only:  \r\n" );
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document.write( "   4.5	 \r\n" );
document.write( "   7.2	 \r\n" );
document.write( "   3.4	 \r\n" );
document.write( "   9.1	 \r\n" );
document.write( "   1.2\r\n" );
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document.write( "Add them:\r\n" );
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document.write( "   4.5	 \r\n" );
document.write( "   7.2	 \r\n" );
document.write( "   3.4	 \r\n" );
document.write( "   9.1	 \r\n" );
document.write( "   1.2\r\n" );
document.write( "------	 \r\n" );
document.write( "  25.4\r\n" );
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document.write( "Divide the sum by 5 to get the mean of the means.\r\n" );
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document.write( "   4.5	 \r\n" );
document.write( "   7.2	 \r\n" );
document.write( "   3.4	 \r\n" );
document.write( "   9.1	 \r\n" );
document.write( "   1.2\r\n" );
document.write( "-------	 \r\n" );
document.write( "5)25.40\r\n" );
document.write( "   5.08\r\n" );
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document.write( "Subtract 5.08 from each of the 5 means\r\n" );
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document.write( "   4.5-5.08=-0.58	 \r\n" );
document.write( "   7.2-5.08= 2.12	 \r\n" );
document.write( "   3.4-5.08=-1.68	 \r\n" );
document.write( "   9.1-5.08= 4.02	 \r\n" );
document.write( "   1.2-5.08=-3.88\r\n" );
document.write( "-------	 \r\n" );
document.write( "5)25.40\r\n" );
document.write( "   5.08\r\n" );
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document.write( "Square each of those:\r\n" );
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document.write( "   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 \r\n" );
document.write( "   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 \r\n" );
document.write( "   3.4-5.08=-1.68   (-1.68)²= 2.8224	 \r\n" );
document.write( "   9.1-5.08= 4.02   ( 4.02)²=16.1604	 \r\n" );
document.write( "   1.2-5.08=-3.88   (-3.88)²=15.0544\r\n" );
document.write( "-------	 \r\n" );
document.write( "5)25.40\r\n" );
document.write( "   5.08\r\n" );
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document.write( "Add those up:\r\n" );
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document.write( "   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 \r\n" );
document.write( "   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 \r\n" );
document.write( "   3.4-5.08=-1.68   (-1.68)²= 2.8224	 \r\n" );
document.write( "   9.1-5.08= 4.02   ( 4.02)²=16.1604	 \r\n" );
document.write( "   1.2-5.08=-3.88   (-3.88)²=15.0544\r\n" );
document.write( "-------	                     ------- \r\n" );
document.write( "5)25.40                      38.8680\r\n" );
document.write( "   5.08\r\n" );
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document.write( "Divide 38.8680 by 1 less than 5, which is 4:\r\n" );
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document.write( "   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 \r\n" );
document.write( "   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 \r\n" );
document.write( "   3.4-5.08=-1.68   (-1.68)²= 2.8224	 \r\n" );
document.write( "   9.1-5.08= 4.02   ( 4.02)²=16.1604	 \r\n" );
document.write( "   1.2-5.08=-3.88   (-3.88)²=15.0544\r\n" );
document.write( "-------	                     ------- \r\n" );
document.write( "5)25.40                    4)38.8680\r\n" );
document.write( "   5.08                       9.7170\r\n" );
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document.write( "That number in red is the variance of the means.\r\n" );
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document.write( "Edwin
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