This might be completely unfeasible or obvious, but I wanted to see if anyone has come across a similar problem. Typical classification methods (decision tree, random forest, etc) require at least two groups to determine group differences, however is it possible to have a singular group, and classify it based on the probability that it's derived from that group or not?
I guess the comparison that comes to mind is a shapiro-Wilk test which determines if a vector is derived from the normal distribution. Is there a method or modelling technique in which you could take a set of variables that characterise a single group, and perform a test to give the probability that it's derived from that group?
Thanks, and apologies if this is really obvious.