document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1058428>Question 1058428</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A final exam in Math 160 has a mean of 73 with a standard deviation of 7.8. If 24 students are randomly selected, find the probability that the mean of their scores is greater than 78. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #673681 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=673681\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a t-test with t(df=23)<BR>\n" );
document.write( "t=(x-mean)/s/sqrt(n)=(x-mean)*sqrt(24)/s<BR>\n" );
document.write( "=(78-73)*sqrt(24)/7.8=3.14<BR>\n" );
document.write( "That is the probability that t df=23 is >3.14.<BR>\n" );
document.write( "From the table, t (0.995,23)=3.10<BR>\n" );
document.write( "The probability or p-value here is <0.005 (it is 0.0046) </SPAN>\n" );
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