Statistics and group analysis: introduction and key points

From standard deviation to WEZ: trust the numbers, not the anecdotes

This is the chapter promised several times in the pages before it: the one that explains why three shots say almost nothing, what standard deviation (SD), extreme spread (ES) and mean radius (MR) actually measure, and how you get from the group to the question that matters: with what probability do I hit that target at that range? Shooting statistics is not academic decoration: it is the antidote to the most human of failings, the tendency to see patterns everywhere, even in noise. The shooter who “feels” that the new charge groups better after five shots is almost always listening to chance; this chapter gives the tools for listening to the data.