document.write( "Question 1186830: The random variable x is the number of girls of 4 children to a couple that is
\n" ); document.write( "equally likely to have a boy or a girl. Among all families with 4 children what is
\n" ); document.write( "the average number of boys? \n" ); document.write( "
Algebra.Com's Answer #817807 by Edwin McCravy(20065)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "It's pretty obvious that on the average they would have 2 boys and 2 girls.\r\n" );
document.write( "There are 24 = 16 possible birth orders for the 4 children listed\r\n" );
document.write( "below:\r\n" );
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document.write( "birth| number\r\n" );
document.write( "order|  of\r\n" );
document.write( "     | boys \r\n" );
document.write( "-------------\r\n" );
document.write( "BBBB |  4\r\n" );
document.write( "BBBG |  3\r\n" );
document.write( "BBGB |  3\r\n" );
document.write( "BBGG |  2\r\n" );
document.write( "BGBB |  3\r\n" );
document.write( "BGBG |  2\r\n" );
document.write( "BGGB |  2\r\n" );
document.write( "BGGG |  1\r\n" );
document.write( "GBBB |  3\r\n" );
document.write( "GBBG |  2\r\n" );
document.write( "GBGB |  2\r\n" );
document.write( "GBGG |  1\r\n" );
document.write( "GGBB |  2\r\n" );
document.write( "GGBG |  1\r\n" );
document.write( "GGGB |  1\r\n" );
document.write( "GGGG |  0\r\n" );
document.write( "---------\r\n" );
document.write( " sum = 32\r\n" );
document.write( "average = 32/16 = 2 boys.\r\n" );
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document.write( "Edwin

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