People would probably like statistics more if the Mahalanobis D 2 statistic was “Ma-Hall-and-Oates-bis” D 2.

I’d made this observation on Facebook a few months ago, but was reminded of it recently when reading about the statistic. Mahalanobis D 2 is a statistic that describes how similar two sets of variables are. In physical anthropology it has often been used to compare shapes of skulls. That is, it has been used to compare the morphological ‘distance’ between pairs of crania, with various inter-landmark distances as variables. This can be problematic, because the statistic is dependent upon the variance-covariance matrix of the sample under study; it has been pointed out often that this variance-covariance matrix cannot really be known or computed for fossil samples, because they’re generally too small, or do not preserve all the same variables.