For introductory statistics, should n be used as
the divisor for the sample variance?
Speed explores the age-old question every statistician is asked to answer at
some point in their career….
the denominator in the sample mean n, but the denominator
for the sample variance is n−1?”
you start talking about sample vs population, parameters vs statistics, bias,
or a personal favorite.. “because you already spent one degree of freedom estimating
the mean.” Either way, it’s never a short,
routine answer and the explanation might depend on the audience asking the
question. Then again, maybe in this day
and age, just get a big enough sample and it doesn’t really matter.