Column replacement operates on a column of the current relation, and supports three distinct types of variables: internals, PointEstimation, and LineFit.
The following getstats internal variables are supported:
$name
From Statistics::PointEstimation (perldoc Statistics::PointEstimation):
$mean
$median
$stdev
$variance
$min
$max
$sum
$count
$mode
$delta
$globals{confidencelevel}
.
From Statistics::LineFit (perldoc Statistics::LineFit):
$slope
$intercept
$lr-rSquared
$lr-durbinWatson
$lr-meanSqError
$lr-sigma
Column replacement implies global replacement.