Add n to summary statistics

[NPS-ARCN-CAKN]

It would be nice to add the number of samples to the available summary statistics. These currently include “mean”, “sd”, “min”, “q1”, “med”, “q3”, “max”, “mad”, “iqr”, “cv”, “skewness”, “se.skewness”, “kurtosis”, “n.valid”, and “pct.valid”. I was always taught to provide the number of values being used to calculate mean, s.d., etc.

Great package BTW!