This project shows the type of interesting material that can be examined by regession analyses. the conclusion is instructive:

It is worth noting that none of the parameters which describe the star system itself, rather than the ease of detection, was not used in the final model. Analysis showed unimportance of them for the purpose of the regression.  Important regression parameters were distance to the star, mass of the planet and detection method. Planet mass indicates only an ease of detection, as big planets are easier to spot. Neither Kepler laws nor modern cosmogony theory implies any relationship between planet’s orbit and mass.

Such a relationship indicates that observed distribution of the extra solar planets is a result of an observational bias, rather than the real distribution of the planets in the galaxy.