document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1197365>Question 1197365</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The number of chocolate chips in an 18-ounce bag of a particular brand of chocolate chip cookies is normally distributed with mean 1,173 chips and standard deviation 115 chips.  \r<BR>\n" );
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document.write( "Calculate the 30th percentile of the number of chocolate chips in an 18-ounce bag of these chocolate chip cookies.  Give your answer as a decimal rounded to two digits after the decimal. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #830627 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=830627\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "mu = 1173 = population mean<BR>\n" );
document.write( "sigma = 115 = population standard deviation\r<BR>\n" );
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document.write( "On a TI83 or TI84 calculator, you will type in the following<BR>\n" );
document.write( "invNorm(0.3)<BR>\n" );
document.write( "This function is found by pressing the key labelled \"2nd\" followed by the VARS key. The invNorm function is the third item.<BR>\n" );
document.write( "The result is approximately -0.5244<BR>\n" );
document.write( "Here's another calculator you can use<BR>\n" );
document.write( "<a  rel=nofollow HREF= \"https://davidmlane.com/normal.html\">https://davidmlane.com/normal.html</a><BR>\n" );
document.write( "Alternatively, you can use the NORMINV function in a spreadsheet.\r<BR>\n" );
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document.write( "What this tells us is<BR>\n" );
document.write( "P(Z < -0.5244) = 0.30 approximately<BR>\n" );
document.write( "In other words, z = -0.5244 is the approximate 30th percentile critical z score.<BR>\n" );
document.write( "About 30% of the area under the Z curve is to the left of z = -0.5244\r<BR>\n" );
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document.write( "Use this z score to find the corresponding x value<BR>\n" );
document.write( "z = (x - mu)/sigma<BR>\n" );
document.write( "z*sigma = x-mu<BR>\n" );
document.write( "x = z*sigma + mu<BR>\n" );
document.write( "x = -0.5244*115 + 1173<BR>\n" );
document.write( "x = 1112.694<BR>\n" );
document.write( "x = 1112.69\r<BR>\n" );
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document.write( "Answer: 1112.69<BR>\n" );
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