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Multiple SETI searches have been going on, what, twenty or thirty years now? That's an impressive statistical sample and I think we can begin to draw some valid statistical inferences from the data; namely, technologically we're IT in the Milky Way (small p, perhaps even p<0.05).

No way can you draw that inference from the SETI data. It's not a question of statistics, it's a question of sensitivity and of coverage. If there were a carbon copy of Earth out there, you wouldn't have to move it very far away before we're highly unlikely to have seen it. We're not close to having looked at our own galaxy exhaustively.

I respectfully disagree. The question from a statistician's point of view is how much our inability to get a true random sample will affect our conclusions. IMHO, I don't think it affects it much.

It's true we don't have a random sample taken from all the stars in our galaxy. But this arm of the galaxy is fairly representative, AFAIK, and we've looked at thousands of stars in the vicinity of the sun. That's a pretty good statistical start, at least when it comes to saying something about the prevalence of advanced civilizations in the galaxy.