Visa operational data, including total volumes, for 2013. $7tn/yr in >256m transactions per day.
Super simple dashboard app, defaults to 2s refreshes and shows the last number. Could be useful in some cases. Supports many backends including InfluxDB, Graphite, more.
Allegedly highly performant time series data store built on top of Cassandra (or by default, an in memory database).
Blog post from bluesmoon / lognormal on how to analyse performance data. Includes some great points on geometric means and geometric standard deviation which better apply to lognormal distributions than arithmetic means / standard deviations. Very useful.
Really handy post with links to sources of web performance optimisation statistics.
Useful online book on statistics. A work in progress, but looks very valuable.
A good introduction to the statistics math of split testing.
Includes the math behind the calculation, and sample PHP code to actually generate the numbers. Very cool.
Simple formula to calculate statistical significance at 95% on AB / split tests. N = total clicks, D = diff between win & lose, if DÂ² > N, it's statistically significant. Example, 14 clicks A, 22 clicks B, N=36, D=22-14=8, 8Â²=64>36, win. If 2DÂ²>N, 99%.
A system to monitor multiple aspects of a live application in production including the page load times, server load times, mysql response times, javascript render times, and so on. Expensive.
QuantCast stats on the WordPress.com hosted network