Complex sentence: Another consequence of the inefficiency of the ordinary least squares fit is that several outliers are masked because the estimate of residual scale is inflated, the scaled residuals are pushed closer to zero than when a more appropriate estimate of scale is used.
Split into simpler sentences: Another consequence of the inefficiency of the ordinary least squares fit is that several outliers are masked. Because the estimate of residual scale is inflated, the scaled residuals are pushed closer to zero than when a more appropriate estimate of scale is used.