pairedDifference

The paired differences as an array for the pair of data names given by the strings. If the data names don't exist then an error occurs. The paired difference is assumed to be named "$s1 - $s2$". If the named difference is not found an empty array is returned.

Return

an array of the paired differences

Parameters

s1

the name of data set number 1

s2

the name of data set number 2