Going back to subject of post momentarily:

As the chart above shows, a public mass shooting occurred on average every 172 days since 1982. The orange reference line depicts this average; data points below the orange line indicate shorter intervals between incidents, i.e., mass shootings occurring at a faster pace. Since September 6, 2011, there have been 14 public mass shootings at an average interval of less than 172 days. A run of nine points or more below the orange average line is considered a statistical signal that the underlying process has changed. (A nine-point run below the average is about as likely to occur by chance as flipping a coin nine times and getting heads nine times in a row—the probability is less than 1 percent. The 14-point run we see here is even more unlikely to have occurred by chance.) The standard interpretation of this chart would be that mass shootings, as of September 2011, are now part of a new, accelerated, process.

Because the chart signals that a new process started around September 2011, we can divide the chart at that point to analyze each phase separately. In the first 29-year phase, mass shootings occurred every 200 days on average. In the subsequent three-year phase, mass shootings occurred every 64 days on average:
Image: shootingsSince2011.png

What’s got this started? Moar gunz? A statistically blip caused by a bow wave of baby boomers with guns hitting the Alzheimer’s zone? An uptick in insane talk show talk?