ref: 3fefdf7e247a5e869097f51716055a386950d3c5
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.