ref: bb88573b7a75f9ec4faaac2e8934964f463c55ec
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.