Variance is a measurement of the spread between numbers in a data set. Investors use the variance equation to evaluate a portfolio’s asset allocation.

Most projects aren't as simple as hiring one contractor to build a deck. In most cases, project managers rely on a formula to calculate schedule variance.

This paper gives alternative derivations for the standard variance formulas in two-stage sampling. The derivations are based on a direct use of the statistical properties of the sampling errors in the ...