SimCovariates ClassA class for specifying covariate distributions and covariance for simulation studies.
covariateslist. List of covariate mean values or probabilities as
generated through bin_var() (class SimVarBin or cont_var()
(class SimVarCont).
covariance_internalmatrix. Covariance matrix before binarization for internal patients.
covariance_externalmatrix. Covariance matrix before binarization for external patients.