document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1036404>Question 1036404</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a random sample of 5,000 exams, the average score was 500 points with a standard deviation of 90 points.\r<BR>\n" );
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document.write( "Find the probability that the true mean is between 495 and 500. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #651157 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=651157\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The z-score is = (value-mean)/s/sqrt (n).  I'm assuming normality here and don't need a t-test with n=5000.<BR>\n" );
document.write( "=(495-500)/90/sqrt(5000)<BR>\n" );
document.write( "=-5(sqrt(5000)/90<BR>\n" );
document.write( "That is a z between -3.92 and 0 or 49.9955% </SPAN>\n" );
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