This monoid stems from the fact that if X and Y are independent random variables
that are normally distributed, then their sum is also
normally distributed, with its new mean equal to the sum of two means
and variance equal to the sum of two variances.
http://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables
This monoid stems from the fact that if X and Y are independent random variables that are normally distributed, then their sum is also normally distributed, with its new mean equal to the sum of two means and variance equal to the sum of two variances. http://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables