Missing data statistics (not installed by default)
 coefficient_of_variation geomean meansq skewness
 covm cor cov corrcoef harmmean median statistic
 detrend kurtosis moment std mad nantest normpdf 
 normcdf norminv sumskipnan meandev rms var mean 
 sem trimean zscore spearman rankcorr ranks 
 quantiles percentile
 
