ref: 00b235d6d62eb18a0327561fea4ba9eae23cdcf7
dir: /stt/variance.t/
The variance of a variable X is computed as...
.Bp
The variance of a variable X is computed as:
.EQ
s sup 2 = {sum from 0 to N ({X sub i} - {X highbar}) sup 2} over {N - 1}
.EN
The substraction in the denominator is related to use of Xbar in the numerator.