The reference vector from which to compute the mean and SD.
robust
Logical, if TRUE, centering is done by subtracting the
median from the variables and dividing it by the median absolute deviation
(MAD). If FALSE, variables are standardized by subtracting the
mean and dividing it by the standard deviation (SD).
digits
Number of significant digits. May also be "scientific"
to return scientific notation. For the latter case, control the number of
digits by adding the value as suffix, e.g. digits = "scientific4"
to have scientific notation with 4 decimal places.