Last week I substitute professed a mathematical statistics course for a friend who was out of town. I was sort of dreading it: interpretation of confidence intervals, Fisher information, AND hypothesis tests, all in one class, less than 24 hours before the start of Thanksgiving break. I didn’t have high hopes for the enthusiasm level in the room. BUT it was actually pretty fun. The Cramer-Rao inequality? It’s really cool that there’s a derivable bound on the variance of an unbiased estimator, and even cooler that that bound happens to be the inverse of the Fisher information. It’s not the kind of stuff that comes up much in my own work or that I’d want to do research on myself, but I got a kick out of teaching it.