Plot of the best-fit L_X(gas) vs. interaction stage (open black squares), including the uncertainty in L_X. The top panel gives the X-ray luminosities only corrected for Galactic absorption. The bottom panel includes internal absorption. The filled blue diamonds are the median values for each stage, slightly offset to the left. The error bars plotted on the median values are the semi-interquartile range, equal to half the difference between the 75th percentile and the 25th percentile. Upper limits above the median were not included in calculating the median. Galaxies containing a Seyfert nucleus are circled in red. The upper limits are 3σ.