document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=333340>Question 333340</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose a survey of 890 families with 5 children was done.<BR>\n" );
document.write( "a. what is the probability of observing children to  be all boys or all girls?<BR>\n" );
document.write( "b.  what is the expected number of families having 3 boys and 2 girls? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #238849 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=238849\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose a survey of 890 families with 5 children was done.<BR>\n" );
document.write( "a. what is the probability of observing children to be all boys or all girls?<BR>\n" );
document.write( "P(all are boys) = (1/2)^890<BR>\n" );
document.write( "P(all are girls) = (1/2)^890<BR>\n" );
document.write( "---<BR>\n" );
document.write( "P(are are boys OR all are girs) = 2*(1/2)^890 = (1/2)^889<BR>\n" );
document.write( "---------------------------------------------------------------<BR>\n" );
document.write( "b. what is the expected number of families having 3 boys and 2 girls?<BR>\n" );
document.write( "P(2 girls in fam. of 5) = 5C2*(1/2)^2*(1/2)^3 = 10*(1/32) = 5/16<BR>\n" );
document.write( "=======================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );