One of my guilty timewasters is playing pipe puzzles on my phone. The rules are fairly simple: you get a grid of pipes and you need to rotate them such that all of the pipes connect with no broken connections and no cycles. I vibecoded a JavaScript implementation to embed here so you can play around to understand the mechanics. If you want to play for real go to puzzle-pipes.com. Solving these individually is certainly a waste of my time. A marginally better use of my time is writing a solver. At least this way I might learn something. ...

How to correct prevalence estimates using PPI

Calibration is an important idea in statistical prediction. However, it’s not the only thing.

I find a strange plot of p-values from a hypothesis test and investigate.

SMBC had a interesting comic recently on correlation chains. It suggests the new “Funtime Activity” of creating correlation chains. As a statistician, I naturally wanted to evaluate the methodology. The basic idea is that you start with a given variable X1 (“Amount of Sex” in the comic) and start by linking to a positively correlated variable X2 (“Happiness”). Then X2 is positively correlated to X3 (“Income”) so you expand the chain to X1 → X2 → X3. Eventually you end up at variable Xn (“Likelihood that you are, in fact, J.K. Rowling”) that’s you conclude is positively correlated the variable X1. ...

How do you sample from a stream of unknown length?