tmcw/simple-statistics — pull request #18 by robbrit (2013-01-03 19:41:00+00:00)
Title: Added sample variances and covariances.

I added sample variances and standard deviations: these are different than the ones for population because a population variance is the average deviation, the sample variance is not. If you use the population variance formula for a sample variance you get a downward bias, more noticeable as the size of the sample gets smaller.

Also added sample covariance and correlation.