Correlations of line luminosity vs. X‐ray luminosity. Open symbols are for radio‐loud quasars. The Spearman rank‐order correlation coefficient (rS) and the two sided significance level (Pr) are indicated above each panel. The strongest correlation is displayed by the Hβ luminosity (which correlates even better with the optical and near IR luminosity). Note the position of the X‐ray–weak quasars. These appear to be fainter by factors of 10–30 in the X‐ray than expected based on their LHβ. This factor is similar to the deficiency seen in Fig. 3.