sample.Skewness() returns population skewness

[kirbatious]

The Statistics class has Skewness() and PopulationSkewness() methods where skewness has a bessel correction.

However if you make a new instance of Sample, the two (extension) methods Skewness() and PopulationSkewness() give the same answer in meta.numerics 4.0.7.

This is because sample.Skewness() actually defaults into the Univariate class implementation of Skewness(), which seems to calculate population skewness.

I believe that either Univariate needs fixing, or Sample needs an override Skewness() method which calls through to the Statistics class, but I don't know which is more sensible.

Example code:

        var sample = new Sample { 2, 2.3, -5.6, 10, -21, 42 };

        var sampleSkewness = Statistics.Skewness(sample);
        var populationSkewness = sample.PopulationSkewness(); // Equivalent to Statistics.PopulationSkewness(sample);
        var alsoPopulationSkewness = sample.Skewness(); // Equivalent to Univariate.Skewness(sample);