document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=117133>Question 117133</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1)	A sample of PVC pipes coming off a production line were tested for pipe diameter size.  The statistical results (in millimeters) were:\r<BR>\n" );
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document.write( "	Mean			300<BR>\n" );
document.write( "	Median			300<BR>\n" );
document.write( "	Mode			300<BR>\n" );
document.write( "	Standard Deviation	15<BR>\n" );
document.write( "	Range			90<BR>\n" );
document.write( "	Number in Sample	100\r<BR>\n" );
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document.write( "a)	According to the Normal Rule, what percent of the pipes had diameters between 285 and 315?  <BR>\n" );
document.write( "b)	What would the range of pipe diameters need to be in order to capture 95% of the pipe diameters?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #85297 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=85297\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1) A sample of PVC pipes coming off a production line were tested for pipe diameter size. The statistical results (in millimeters) were: <BR>\n" );
document.write( "Mean 300<BR>\n" );
document.write( "Median 300<BR>\n" );
document.write( "Mode 300<BR>\n" );
document.write( "Standard Deviation 15<BR>\n" );
document.write( "Range 90<BR>\n" );
document.write( "Number in Sample 100 <BR>\n" );
document.write( "a) According to the Normal Rule, what percent of the pipes had diameters between 285 and 315? <BR>\n" );
document.write( "Find z-scores for 285 and for 315:<BR>\n" );
document.write( "z(285) = (285-300)/15=-1 <BR>\n" );
document.write( "z(315) = (315-300)/15=+1<BR>\n" );
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document.write( "Then P(-1<z<1) = 68%<BR>\n" );
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document.write( "b) What would the range of pipe diameters need to be in order to capture 95% of the pipe diameters?<BR>\n" );
document.write( "Find the z-score corresponding to 95%<BR>\n" );
document.write( "Use your z-chart or InvNorm(0.95) to get z=1.645<BR>\n" );
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document.write( "Then find the raw score associated with that z-score:<BR>\n" );
document.write( "1.645 = (x-300)/15<BR>\n" );
document.write( "x-300 = 24.67<BR>\n" );
document.write( "x = 324.67<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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