document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1149161>Question 1149161</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A group of more than 1000 students took a test in Mathematics and their final grades have a mean of 70 and a standard deviation of 10. If we can approximate the distribution of these grades by a normal distribution, what percent of the students\r<BR>\n" );
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document.write( "(a) scored higher than 80?<BR>\n" );
document.write( "(b) should pass the test (grades ≥ 60)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #770519 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=770519\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> (a)  Probability (P) (X > 80) = 1 - P(X < 80)<BR>\n" );
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document.write( "z-score(80) = (80 - 70)/10 = 1<BR>\n" );
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document.write( "Lookup a z-score of 1 in the table of z-values and its associated P<BR>\n" );
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document.write( "P(X < 80) = 0.8413<BR>\n" );
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document.write( "P(X > 80) = 1 - 0.8413 = 0.1587<BR>\n" );
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document.write( "(b)  z-score(60) = (60 -70)/10 = -1<BR>\n" );
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document.write( "P(X < 60) = 0.1587<BR>\n" );
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document.write( "P(X > 60) = 1 - 0.1587 = 0.8413<BR>\n" );
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