On 6/27/07, Eldon Eller <[EMAIL PROTECTED]> wrote:
Argument by reductio ad absurdum: Consider the standard deviation of a data set consisting of a single point. Using N for the denominator gives a standard deviation of zero, which is correct only if that point is the entire population.
Sure -- and it IS correct when all members of the population are the same. If you have only a single point and it is not the entire population, then your problem is that you've not collected enough data to properly represent deviation.
Using N-1 gives a standard deviation of 0%0, which is indeterminate, and is correct if that point is a sample from a larger population.
"Indeterminate" is a non answer, not a correct answer. And you have the same underlying issue when N is greater than 1, if your samples happen to have the same values. -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
