document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1103585>Question 1103585</A>: <I><SPAN STYLE=\"word-break: break-all;\"> According to the records of an electric company serving the Boston area, the mean electricityconsumption for all households during winter is 1650 kilowatt-hours per month.  Assume that themonthly electricity consumptions during winter by all households in this area have a normal dis-tribution with a mean of 1650 kilowatt-hours and a standard deviation of 320 kilowatt-hours.  Thecompany sent a notice to Bill Johnson informing him that about 90% of the households use lesselectricity per month than he does.  What is Bill Johnson's monthly electricity consumption? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #718329 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=718329\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Normal distribution with mean is 1650 and sd is 320.<BR>\n" );
document.write( "Basically, 90th percentile of z is +1.282<BR>\n" );
document.write( "z=(x-mean)/sd<BR>\n" );
document.write( "1.282=(x-1650)/320<BR>\n" );
document.write( "410.24=x-1650<BR>\n" );
document.write( "x=2060 kwh.\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );