document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=849645>Question 849645</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A small business just leased a new computer and color laser printer for three years. The service<BR>\n" );
document.write( "contract for the computer offers unlimited repairs for a fee of $100 a year plus a $25 service charge for<BR>\n" );
document.write( "each repair needed. The company’s research suggested that during a given year 86% of these<BR>\n" );
document.write( "computers needed no repairs, 9% needed to be repaired once, 4% twice, 1% three times, and none<BR>\n" );
document.write( "required more than three repairs.\r<BR>\n" );
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document.write( "a) Find the expected number of repairs this computer needs each year\r<BR>\n" );
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document.write( "b.)The standard deviation of the number of repairs each year is 0.55. What is the standard deviation of<BR>\n" );
document.write( "the company's annual expense for the service contract? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #511674 by </B><A HREF=/tutors/aboutme.mpl?userid=swincher4391><B>swincher4391(1107)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=swincher4391><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=swincher4391><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=511674\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1)  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0%28.86%29+%2B+1%28.09%29+%2B+2%28.04%29+%2B+3%28.01%29+=+highlight%280.2%29 ALIGN=MIDDLE  ALT=\"0%28.86%29+%2B+1%28.09%29+%2B+2%28.04%29+%2B+3%28.01%29+=+highlight%280.2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "2)  E[annual expense] = 100(.86) + 125(.09) + 150(.04) + 175(.01) = 105\r<BR>\n" );
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document.write( "E[(annual expense)^2] = 100^2(.86) +125^2(.09) + 150^2(.04) + 175^2(.01) = 11212.5\r<BR>\n" );
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document.write( "I'll short hand annual expense = A.\r<BR>\n" );
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document.write( "Var[A] = E[A^2] -[E[A]]^2\r<BR>\n" );
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document.write( "Var[A] = 11212.5 - 105^2 = 187.5\r<BR>\n" );
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document.write( "SD[A] = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%28Var%28A%29%29+=+sqrt%28187.5%29+=+highlight%2813.69%29 ALIGN=MIDDLE  ALT=\"sqrt%28Var%28A%29%29+=+sqrt%28187.5%29+=+highlight%2813.69%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
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