The<unk> , also known as the Huber<unk> <unk> r and the<unk><unk> <unk> r, can be used to<unk>  the variance of an ordinary least squares (OLS) regression when the underlying model is incorrect, such as in the case of homoscedasticity.  The<unk> <unk> r is generally only used when the OLE model has serious error and may benefit the variance, but the parameters being<unk> d by the OLE become meaningless to interpret .
Robust Sandwich Covariate Estimate
Ancillary statistic
Absolute deviation
Non-parametric statistics
Attributable risk
Degrees of freedom 
Fixed effects estimation
Random variable