Estimating Variance Simulation
David M. Lane
The average squared difference from the sample mean
will, on average, underestimate the population variance.
In some samples it will overestimate it, but most of the time it will underestimate
it. If the formula is modified so that the sum of squared deviations is divided
by N -1 rather than by N, then the tendency to underestimate the populationvariance is eliminated.
Please answer the questions: