Pearson correlation coefficient and covariance of two equal-length paired series. Rejected as a clean 400 if the lengths differ or either series has zero variance (correlation undefined).

Evaluate one or more percentiles (0–100) of a numeric sample using linear interpolation between order statistics (the R-7 / Excel PERCENTILE.INC method). 50 is the median, 25/75 the quartiles.

Ordinary-least-squares linear regression of y on x: slope, intercept, correlation r and coefficient of determination r². Pass predictAt to also evaluate the fitted line at a given x. Rejected as a clean 400 if lengths differ or x has zero variance.

Full descriptive summary of a numeric sample: count, sum, min/max/range, mean, median, mode(s), variance, standard deviation and the quartiles (q1/q3/iqr). Set sample=true for the sample variance/stdev (÷ n-1) instead of the population form (÷ n).