Why are there so few Coronavirus cases in Ohio? They haven't tested anyone.

Okay, the headline is a bit of an exaggeration, but only by so much. It is being reported that New York is the epicenter of the coronavirus epidemic. Part of the reason for that is that 26% (79,000) of all US tests have been conducted there. On the opposite end of the spectrum is Ohio where only 582 people have been tested.

This is just another instance of the need to understand how data are collected in order to be able to accurately determine what they actually mean.