document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=440446>Question 440446</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If I have a 5 yr. old boy who has a BMI of 18 and the BMI is considered a normally distributed variable, whose mean for this age boy is 15.41914 and whose standard deviation is 0.075992.  How can I calculate the PERCENTILE ranking for this boy.  Please show me HOW you achieve the numbers--I need to see HOW to calculate the result--PLEASE DO NOT USE A TABLE.  I want to write an excel program for our school nurse and I need the EQUATION to plug in and test for in excel.  Thank you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #304251 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=304251\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If I have a 5 yr. old boy who has a BMI of 18 and the BMI is considered a normally distributed variable, whose mean for this age boy is 15.41914 and whose standard deviation is 0.075992. How can I calculate the PERCENTILE ranking for this boy. Please show me HOW you achieve the numbers--I need to see HOW to calculate the result.<BR>\n" );
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document.write( "1st: Find the z-value of 18<BR>\n" );
document.write( "using the equation: z(x) = (x-u)/sigma<BR>\n" );
document.write( "z(18) = (18-15.41914)/0.075992 = 2.580860/0.075992 = 33.962259<BR>\n" );
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document.write( "Note: z is a measure of the number of standard deviations the<BR>\n" );
document.write( "score is above the mean of the distribution.<BR>\n" );
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document.write( "By the way, a z-score of 33.96.. is extremely unusual.<BR>\n" );
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document.write( "2nd: Find the percent of BMI scores that are less than 18.<BR>\n" );
document.write( "That percent is the percent of a normally distributed population<BR>\n" );
document.write( "that is less than z = 33.962259<BR>\n" );
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document.write( "3rd: Use a Statistical z-chart or an EXCEL function to find<BR>\n" );
document.write( "P(x < 18) = P(z < 33.962259) is approximately 100%ile.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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