document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=967190>Question 967190</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the probability that in a sample of 10 drivers exactly 4 will have a medical aid<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #591166 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=591166\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> you don't have enough information to determine this.\r<BR>\n" );
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document.write( "if this is a binomial probability type problem, what you need is the proportion of the population of drivers that has a medical aid in general.\r<BR>\n" );
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document.write( "assuming that proportion is 20% of the population of drivers, then you would get the following:\r<BR>\n" );
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document.write( "p = .2<BR>\n" );
document.write( "q = 1 - p = .8<BR>\n" );
document.write( "n = 10<BR>\n" );
document.write( "x = 4\r<BR>\n" );
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document.write( "the general formula is p(x) = c(n,x) * p^x * q^(n-x)\r<BR>\n" );
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document.write( "in your probolem, the formula would become p(4) = c(10,4) * .2^4 * .8^6 which would then become p(4) = 210 * .2^4 * .8^6 which becomes p(4) = .088080384.\r<BR>\n" );
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document.write( "if that proportion were 40%, then the formula would become p(4) = 10c4 * .4^4 * .6^6 which would then become p(4) = .250822656.\r<BR>\n" );
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document.write( "c(10,4) is the combination formula for how many sets of 4 can you get out of 10 things where order is not important.\r<BR>\n" );
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document.write( "c(10,4) = 10! / (4! * 6!) which is equal to 210.\r<BR>\n" );
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