document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=858772>Question 858772</A>: <I><SPAN STYLE=\"word-break: break-all;\"> According to records of commonwealth Edison, the mean electric consumption <BR>\n" );
document.write( "during January is 1,650 kilowatt hours, with a standard deviation of 320 <BR>\n" );
document.write( "kilowatt hours. The monthly electric consumption for January follows a normal <BR>\n" );
document.write( "distribution.\r<BR>\n" );
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document.write( "a. Selecting a customer at random, find the probability that the customer uses <BR>\n" );
document.write( "less than 1,000 kilowatt hours in January.\r<BR>\n" );
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document.write( "b. Selecting a customer at random, find the probability than the customer uses <BR>\n" );
document.write( "between 1,500 and 2,500 kilowatt hours in January.\r<BR>\n" );
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document.write( "c. Commonwealth Edison wants to identify its heaviest users, which are those <BR>\n" );
document.write( "that are in the top 6% of electric consumption. How many kilowatt hours in <BR>\n" );
document.write( "January would qualify for the heavy user classification?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #517390 by </B><A HREF=/tutors/aboutme.mpl?userid=psbhowmick><B>psbhowmick(878)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=psbhowmick><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=psbhowmick><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=517390\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a) Let the electric consumption be the random variable X and normally distributed with mean <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=mu ALIGN=MIDDLE  ALT=\"mu\"   DISABLED_style= \"max-width:90%; height:auto;\" > and standard deviation <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sigma ALIGN=MIDDLE  ALT=\"sigma\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "At first calculate the Z-score corresponding to 1000 kilowatt hours.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Z=%28X-mu%29%2Fsigma=%281000-1650%29%2F320=-650%2F320=-2.03125 ALIGN=MIDDLE  ALT=\"Z=%28X-mu%29%2Fsigma=%281000-1650%29%2F320=-650%2F320=-2.03125\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "To find the probability that a house uses less than 1000 kilowatt hours of electricity:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=p%28X%3C1000%29+=+p%28Z%3C2.03125%29+=+0.02 ALIGN=MIDDLE  ALT=\"p%28X%3C1000%29+=+p%28Z%3C2.03125%29+=+0.02\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Try the other parts yourself. If you still need help then contact me. \r<BR>\n" );
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document.write( "Cheers!!! </SPAN>\n" );
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