Present propensity scores (now unit 6) before "multivariate distance matching" (unit 5)?

[benthestatistician]

I propose to upend the current ordering of material in units 5 and 6. Partly this is to try to bring my 1/2 of the 4 week course to a sensible stopping points, partly out of a hope that I'll find time to say a little about inverse probability weighting in its application to experiments. (This connects to the propensity score on a conceptual level, and may help to bridge from the RCT focus of weeks 1 and 2 toward including more observational studies methods in weeks 3 and 4.)

I'll just go ahead and do it w/o further posting here -- unless somebody posts a comment that causes me to reconsider, of course.

[benthestatistician]

Done in [master 4eb05e95]