Re: Quick question

On Jul 14, 10:43 am, henrysun...@xxxxxxxxx wrote:
Can someone give me a rule that tells me when to use n trials in the
denominator when determining variance and when to use n-1?

Openoffice calc (spread*** program) appears to use n-1, and yet some
of the references I've been studying use n. Obviously, the smaller
denominator will give a larger variance and standard deviation, so
clarification on this would be greatly appreciated.

Thanks in advance.

Henry Sun

It depends on what you want to talk about. If you divide by n you get
the variance of the data. If you divide by n-1 you get an estimate of
the variance of the population from which the data were drawn. So n
gets you a description of the data in hand, whereas n-1 gets you an
inference about the population that the data came from.
.