document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=414490>Question 414490</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A normal distribution of weekly income has a mean of $250 and a standard deviation of $20. Approximately what proportion of people earn between $240 and $260 a week? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #290709 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=290709\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A normal distribution of weekly income has a mean of $250 and a standard deviation of $20. Approximately what proportion of people earn between $240 and $260 a week?<BR>\n" );
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document.write( "z(240) = (240-250)/20 = -1/2<BR>\n" );
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document.write( "z(260) = (260-250)/20 = +1/2<BR>\n" );
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document.write( "Proportion(240<= x <=260) = P(-1/2 <= z <=1/2) = 0.3829<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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