document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=465483>Question 465483</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have no idea of how to approach this word problem. Can you please show me step by step how to solve this problem?\r<BR>\n" );
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document.write( "The mean IQ score of 1500 students is 100 with a standard deviation of 15. How many have an IQ between 85 and 115? How many have an IQ between 70 and 130? How many have an IQ of 145? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #318979 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=318979\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I have no idea of how to approach this word problem. Can you please show me step by step how to solve this problem? <BR>\n" );
document.write( "The mean IQ score of 1500 students is 100 with a standard deviation of 15. <BR>\n" );
document.write( "How many have an IQ between 85 and 115? <BR>\n" );
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document.write( "z(85) = (85-100)/15 = -1<BR>\n" );
document.write( "z(115) = (115-100)/15 = +1<BR>\n" );
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document.write( "%(85<= x <= 115) = %(-1<= z <=1) = 0.6827<BR>\n" );
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document.write( "# with IQ between 85 and 115 = 0.6827*1500 = 1024 when rounded down<BR>\n" );
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document.write( "How many have an IQ between 70 and 130? <BR>\n" );
document.write( "Same Procedure:<BR>\n" );
document.write( "z(70) = (70-100)/15 = -2<BR>\n" );
document.write( "z(130) = (130-100)/15 = 2<BR>\n" );
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document.write( "%(70<= x <= 130) = %(-2<= z <=2) = 0.9545<BR>\n" );
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document.write( "# with IQ between 70 and 130 = 0.9545*1500 = 1432 when rounded up<BR>\n" );
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document.write( "How many have an IQ of 145?<BR>\n" );
document.write( "Ans: zero<BR>\n" );
document.write( "Why?  In a normal distribution the probability of<BR>\n" );
document.write( "any particular value is zero. <BR>\n" );
document.write( "Why?  The area over a point is zero because the base is zero.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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