Chapter 6 Some Multivariate Methods 255 6.6.1 R Function gvarg The R function gvarg(m,var.fun=cov.mba, . . .) a robust generalized variance for the data stored in the argument m. By default, the RMBA covariance matrix is used because other methods to be described appear to perform reasonably well based on this covariance matrix. The command gvarg(x,skipcov,MM=F) would compute the generalized variance based on the OP-estimate of scatter in conjunction with Carling's modification of the boxplot rule. The command gvarg(x,skipcov,MM=T) would use the MAD-median rule. 6.7 Inference in the One-Sample Case