Re: The calculator is correct Message #9 Posted by rsenzer on 25 July 2002, 7:56 p.m., in response to message #8 by Xtian
Hi Xtian,
I can't answer directly because I don't have a 42S. However, I have performed the calculations on a 32SII. The result of squaring the sample standard deviation on this calculator is :
174.999999999
So I think it's just a matter of rounding error.
The more important issue is distinguishing between sample statistics, which use a denominator of (N  1) based on loss of a degree of freedom, and the population statistics, which use a denominator of N. [N being the number of data points.] On the 32SII, the sample standard deviation is given by s_{x} whereas the population standard deviation is given by
[lower case greek letter] sigma_{x}.
If a calculator has only one or the other, then
sigma_{x}^{2} =
[(N  1) / N] * s_{x}^{2}
and
s_{x}^{2} =
[N / (N  1)] * sigma_{x}^{2}
Just take the square root to compute sigma_{x} or s_{x}.
