Central Limit Theorem -- Dickeson

Looking at Web Speeds
Above is a chart of net running speed samples of a web offset press applying Central Limit Theory. It has the six-sigma control range plotted in as the UCL and LCL. We predict, with 99.7 percent probability, that the net speed of all runs on this press will fall between 28.86 and 20.16 thousand impressions per hour (iph). Any run faster or slower than these limits is due to special causes that need investigation.