cutByQuantile: Calculates the "center" quantiles, always including the median.
Description
If the numeric variable has fewer than 6 unique observed
values, this will send the data to cutByTable. The
default return will find dividing points at three
quantiles: c(0.25, 0.50, 0.75) If n=4, the dividing
points will be c(0.20, 0.40, 0.60, 0.80) If n=5, c(0.10,
0.30, 0.50, 0.70, 0.90) Larger n that are odd will
include 0.5 and evenly spaced points out to 0 and 1.
Larger n that is even will return evenly spaced points
calculated by R's pretty function.