document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=126062>Question 126062</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A random sample of 100 students who took a statistics exam were asked their score on the exam.  The mean score on the test was 50; the standard deviation was 10.  The scores are normally distributed.  <BR>\n" );
document.write( "A) What percent of the students scored below 30?  <BR>\n" );
document.write( "B) What percent scored between 30 and 55?<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 #92373 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=92373\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A random sample of 100 students who took a statistics exam were asked their score on the exam.  The mean score on the test was 50; the standard deviation was 10.  The scores are normally distributed.  <BR>\n" );
document.write( "A) What percent of the students scored below 30?<BR>\n" );
document.write( "Find the t-score 30<BR>\n" );
document.write( "t(30) = (30-50)/10 = -2<BR>\n" );
document.write( "Find Prob(t<-2); you get  0.0241..<BR>\n" );
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document.write( "B) What percent scored between 30 and 55?\r<BR>\n" );
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document.write( "t(55) = (55-30) / 10 = 2.5<BR>\n" );
document.write( "t(30) = (30-30) / 10 = 0<BR>\n" );
document.write( "P(0 < t < 2.5) = 0.4929..\r<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );