var function from the method in order to report the variance of circular data
appropriatly. var.default is an alias of the original function
var. The behavior would be the same for objects which are not
from class data.frame and
circular (in the last case the variance is define as one
minus the mean resultant length divided by the sample size of data, see
var.circular for more details). The method for
data.frame will apply the var function to each columns.var(x, ...)
## S3 method for class 'default':
var(x, y = NULL, na.rm = FALSE, use, \dots)
## S3 method for class 'data.frame':
var(x, \dots)NULL (default) or a vector, matrix or data frame with
compatible dimensions to x. The default is equivalent to
y = x (but more efficient)."all.obs", "complete.obs" or "pairwise.complete.obsvar, var.circular, rho.circular and summary.circular.