How Reliable will the Falcon 9 be?

D'oh. I had to fix all of my numbers.

The bottom line is that if we a priori thought that all possible reliabilities for the engine were equally likely, then based on current data we'd currently estimate a 3.6% failure rate per launch. That's significantly worse than the shuttle. However if there are a few more successful launches, then those numbers will improve rapidly.

I leave updating the simple proof of concept script that I put up to handle arbitrary numbers of launches and engine failures as an exercise for the reader.