document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=628465>Question 628465</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If boys and girls are equally likely and groups of 400 births are randomly selected. Find the standard deviation of the numbers of girls in such groups of 400.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #395645 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=395645\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This sounds like a binomial distribution problem.\r<BR>\n" );
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document.write( "Standard deviation:\r<BR>\n" );
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document.write( "sigma = sqrt(n*p*(1-p))\r<BR>\n" );
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document.write( "sigma = sqrt(400*0.5*(1-0.5))\r<BR>\n" );
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document.write( "sigma = 10\r<BR>\n" );
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document.write( "So the standard deviation is 10. </SPAN>\n" );
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