document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1200458>Question 1200458</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this probability question<BR>\n" );
document.write( "The shelf life of a product has a mean, ū=10days and a standard deviation of 3 days. Assuming a normal distribution, determine the probability of a product lasting for <BR>\n" );
document.write( "a) between 7 days and 13days<BR>\n" );
document.write( "b) fewer than 7days\r<BR>\n" );
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document.write( "Thank you very much  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #834601 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52814)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=834601\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .<BR>\n" );
document.write( "Please help me with this probability question<BR>\n" );
document.write( "The shelf life of a product has a mean, ū=10days and a standard deviation of 3 days. <BR>\n" );
document.write( "Assuming a normal distribution, determine the probability of a product lasting for<BR>\n" );
document.write( "a) between 7 days and 13days<BR>\n" );
document.write( "b) fewer than 7days<BR>\n" );
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document.write( "<PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "Using calculators like TI-83 or TI-84, call standard function normalcdf.\r\n" );
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document.write( "    \"normalcdf\" stands for cumulative normal distribution function.\r\n" );
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document.write( "Its format is normalcdf(z1,z2,m,SD), where z1 and z2 are raw z-marks, m is the mean \r\n" );
document.write( "and SD is the standard deviation.\r\n" );
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document.write( "For question (a), the probability is the area under the specified normal curve\r\n" );
document.write( "between the raw marks 7 and 13\r\n" );
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document.write( "    P = normalcdf(7, 13, 10, 3) = 0.6827.    <U>ANSWER</U>\r\n" );
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document.write( "For question (b), the probability is the area under the specified normal curve\r\n" );
document.write( "on the left of the raw mark 7\r\n" );
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document.write( "    P = normalcdf(-9999, 7, 10, 3) = 0.1587.    <U>ANSWER</U>\r\n" );
document.write( "</PRE>\r<BR>\n" );
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document.write( "Solved.\r<BR>\n" );
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document.write( "---------------\r<BR>\n" );
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document.write( "If you want to get better understanding, use online free of charge calculator <BR>\n" );
document.write( "at web-site https://onlinestatbook.com/2/calculators/normal_dist.html\r<BR>\n" );
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document.write( "It has simple and intuitively clear interface.<BR>\n" );
document.write( "In addition, it shows you a diagram with the area of interest shaded,<BR>\n" );
document.write( "so at any time moment you do understand what you are doing<BR>\n" );
document.write( "and what the calculator does.\r<BR>\n" );
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document.write( "After playing with this online calculator, you will learn the subject enough.<BR>\n" );
document.write( "After that, you may switch to ordinary calculator TI-83 or TI-84.\r<BR>\n" );
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document.write( "=================\r<BR>\n" );
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document.write( "If you need instructions on using function normalcdf in ordinary calculators, look at this link\r<BR>\n" );
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document.write( "https://www.usu.edu/math/cfairbourn/calculatorhelps/normalcdfti-84.pdf\r<BR>\n" );
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document.write( " </SPAN>\n" );
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