The attached spreadsheet has a dataset of: 2,4,6,8,10,12
The following excel functions give results:
Then In Java, if I code like so:
org.apache.commons.math.stat.descriptive.moment.Variance variance = new Variance();
double sigma = variance.evaluate(myDoubleArray);
where myDoubleArray contains 2.0, 4.0, 6.0, 8.0, 10.0, 12.0
then sigma is 14.0.
So I would conclude that the variance calculated by Commons Math is a sample variance not a population variance.
How would I calculate a sample variance using Commons Math?