document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=774258>Question 774258</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The probability that twins are identical is 0.4. While identical twins are always of the same sex, there is only a 48% chance that twins will be of the same sex if they are not identical. We define the random variable X as follows:\r<BR>\n" );
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document.write( "X= 1 If we hav identical twins that are of the same sex<BR>\n" );
document.write( "   2 If we have identical twins that are of different sexes<BR>\n" );
document.write( "   3 If we have non-identical twins that are of the same sex<BR>\n" );
document.write( "   4 If we have non-identical twins that are of different sexes\r<BR>\n" );
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document.write( "a) Determine the probability mass function associated with the random variable  defined as X.<BR>\n" );
document.write( "b) Draw the p.m.f. of X.<BR>\n" );
document.write( "c) Let A be the even that the twins are of the same sex. What is Pr(A)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #472152 by </B><A HREF=/tutors/aboutme.mpl?userid=oscargut><B>oscargut(2103)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oscargut><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/cgi-bin/show-face.mpl?user=oscargut><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=472152\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The probability that twins are identical is 0.4. While identical twins are always of the same sex, there is only a 48% chance that twins will be of the same sex if they are not identical. We define the random variable X as follows:\r<BR>\n" );
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document.write( "X= 1 If we hav identical twins that are of the same sex<BR>\n" );
document.write( "   2 If we have identical twins that are of different sexes<BR>\n" );
document.write( "   3 If we have non-identical twins that are of the same sex<BR>\n" );
document.write( "   4 If we have non-identical twins that are of different sexes\r<BR>\n" );
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document.write( "a) Determine the probability mass function associated with the random variable  defined as X.<BR>\n" );
document.write( "b) Draw the p.m.f. of X.<BR>\n" );
document.write( "c) Let A be the even that the twins are of the same sex. What is Pr(A)?\r<BR>\n" );
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document.write( "Solution: (i do the first part)\r<BR>\n" );
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document.write( "a)\r<BR>\n" );
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document.write( "P(X=1) = 0.4\r<BR>\n" );
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document.write( "P(X=2) = 0\r<BR>\n" );
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document.write( "P(X=3) = 0.6(0.48)=0.288\r<BR>\n" );
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document.write( "P(X=4) = 0.6(0.52) = 0.312\r<BR>\n" );
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document.write( "I can help you with more questions at: mthman@gmail.com\r<BR>\n" );
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document.write( "Thanks\r<BR>\n" );
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document.write( " </SPAN>\n" );
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