Differences in υ_los measured with the maximum likelihood (v_MLM) and the cross-correlation (v_Xcorr) methods as a function of the S/N per pixel for the individual VLT/FLAMES LR8 spectra of likely RGB members of the Sextans dSph with G < 19.7. Red star symbols represent those stars that do not meet the EW criterion. The vertical dotted blue line shows the minimum acceptable S/N = 10, and the horizontal dotted blue lines show the limits for outliers, at ±4 km/s. The dotted black line is at v_MLM − v_Xcorr = 0. The dashed red lines are the running mean for the combined direct error estimates made on the individual velocity measurements from the two different methods.