<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Times New Roman; font-size: 12pt; color: #000000'><P>Norma,</P>
<P>It would seem that since you only had 3 significant figures in each of the original measurements, that the calculated mean/average of 7.513333333...would be rounded and reported as 7.51 g.cm3, or the whole purpose of using significant figures would be lost. </P>
<P>The other thing that might be necessary if you were reporting these widely spaced data are a box and whisker plot or some other statistical devices that would convey the range of values in the group. </P>
<P>Larry</P>
<P>Larry Sherer</P>
<P><BR>----- Original Message -----<BR>From: "Norma Holowach" <norma.holowach@neomin.org><BR>To: "YAPA YAPA" <yapa@lists.ysu.edu><BR>Sent: Friday, September 11, 2009 11:12:20 AM GMT -05:00 US/Canada Eastern<BR>Subject: [YAPA] significant figures and averages<BR><BR></P>
<P>Working with significant figures and averaging several trials can lead to some awkward answers. For example if I have the following results for the density of a solid: 7.55 g/cm3, 8.10g/cm3, 6.89g/cm3 the total would be 22.54 g/cm3 divided by the three trials and appears that there should be 4 significant figures listed for the average, 7.513g/cm3. This does not seem right that the average would be written to the thousandths place when the trials only went to the hundreth place. What am I missing here? </P>
<P><BR>Norma Holowach, M.Ed <BR>National Board Certified Teacher <BR>Science Department Chairperson <BR>Lakeview High School <BR>300 Hillman Drive <BR>Cortland, OH 44410 <BR>(330)637-4921 <BR>"Connecting with nature is an essential part of being alive." <BR>National Geographic. <BR></P><BR>_______________________________________________ YAPA mailing list YAPA@lists.ysu.edu http://lists.ysu.edu/mailman/listinfo.cgi/yapa </div></body></html>