document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=227163>Question 227163</A>: <I><SPAN STYLE=\"word-break: break-all;\"> You are given the following frequency distribution for the number of errors that students made in a test <BR>\n" );
document.write( " Errors..... Frequency<BR>\n" );
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document.write( "0-2..... 11<BR>\n" );
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document.write( "3-5..... 9<BR>\n" );
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document.write( "6-8..... 7<BR>\n" );
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document.write( "9-11..... 7<BR>\n" );
document.write( " <BR>\n" );
document.write( "12-14..... 13<BR>\n" );
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document.write( "Find the mean, variance, and standard deviation.<BR>\n" );
document.write( "Please figure this problem out. It is so confusing. Thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #169190 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=169190\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You are given the following frequency distribution for the number of errors that students made in a test <BR>\n" );
document.write( "Errors..... Frequency\r<BR>\n" );
document.write( "\n" );
document.write( "0-2..... 11\r<BR>\n" );
document.write( "\n" );
document.write( "3-5..... 9\r<BR>\n" );
document.write( "\n" );
document.write( "6-8..... 7\r<BR>\n" );
document.write( "\n" );
document.write( "9-11..... 7\r<BR>\n" );
document.write( "\n" );
document.write( "12-14..... 13\r<BR>\n" );
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document.write( "Find the mean, variance, and standard deviation.<BR>\n" );
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document.write( "Use the class mark as the representative value for each class.<BR>\n" );
document.write( "Multiply each class mark by the frequency of the class; then add the products.<BR>\n" );
document.write( "Divide the sum (above) by the sum of the frequencies to get the mean.<BR>\n" );
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document.write( "I used a TI calculator to get:<BR>\n" );
document.write( "mean = 7.1277<BR>\n" );
document.write( "variance = 21.43<BR>\n" );
document.write( "stand deviation = sqrt(variance) = 4.6293<BR>\n" );
document.write( "==============================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );