document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1183046>Question 1183046</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A company hires management trainees for entry-level sales positions. Past experience indicates that only 10% will still be employed at the end of 9 months. Assume the company recently hired 6 trainees.<BR>\n" );
document.write( "a. What is the probability that three of the trainees will still be employed at the end of 9 months?<BR>\n" );
document.write( "b. What is the probability that at least two of the trainees will still be employed at the end of 9 months?<BR>\n" );
document.write( "c. What is the expected number of trainees that will still be employed at the end of 9 months?<BR>\n" );
document.write( "d. What is the standard deviation of the number of trainees that will still be employed at the end of 9 months? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #813191 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=813191\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is 6C3(0.1)^3*(0.9)^3<BR>\n" );
document.write( "the 6C3 are the number of ways three may be chosen from 6 (20).<BR>\n" );
document.write( "=0.01458<BR>\n" );
document.write( "-<BR>\n" );
document.write( "Look at prob (0) and prob (1) and subtract that from 1. This will give the probability of at least 2. The prob. of 0 is .9^6=0.5314<BR>\n" );
document.write( "1 is 6*.9^5*.1=0.3542<BR>\n" );
document.write( "=0.8856<BR>\n" );
document.write( "So the probability of at least two is 0.1144<BR>\n" );
document.write( "E(X)=np =6*0.1=0.6 trainees<BR>\n" );
document.write( "Var(X)=np(1-p)=0.6*0.9=0.54<BR>\n" );
document.write( "sd is sqrt(V)=0.7348 trainees\r<BR>\n" );
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document.write( " </SPAN>\n" );
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