document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1105643>Question 1105643</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Statistics students participated in an experiment to test their ability to determine when 1 minute&#8203; (or 60&#8203; seconds) has passed. The results are given below in seconds. Find the&#8203; range, variance, and standard deviation for the given sample data. Identify one reason why the standard deviation from this sample might not be a good estimate of the standard deviation for the population of adults.<BR>\n" );
document.write( "51,53,60,69,56\r<BR>\n" );
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document.write( "I KNOW THE RANGE IS 18 SECONDS <BR>\n" );
document.write( "BUT NEED HELP WITH SAMPLE VARIANCE <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 #720656 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=720656\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Mean is 57.8<BR>\n" );
document.write( "the variance is the sum of squares of the differences divided by 4, calling this a sample and not a population<BR>\n" );
document.write( "-6.8^2+-4.8^2+2.2^2+11.2^2-1.8^2=202.8/4=50.7; sd is sqrt of that.<BR>\n" );
document.write( "Reasons why this sd might not be a good estimate:<BR>\n" );
document.write( "1. Small sample size<BR>\n" );
document.write( "2. Youth (likely), with different memory.<BR>\n" );
document.write( "3. Students, so those without same education may not be the same.<BR>\n" );
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