varianceOfDifference

The variance for the pair of data names given by the strings. If the data names don't exist or the difference "

$s1 - $

s2" or "

$s2 - $

s1" does not exist then an exception will occur. The variance of the differences are symmetric. That is variance of "

$s1 - $

s2" is equal to the variance of "

$s2 - $

s1".

Return

variance for the pair of data names given by the strings "

$s1 - $

s2" or "

$s2 - $

s1"

Parameters