Central Limit Theorem -- Dickeson

The Central Limit Theorem (CLT) of statistics tells us that the averages of a group of individual samples will be approximately "normally" distributed. (CLT is the theory used by Deming/Shewhart in charting control limits for product variances.) For printing it can be applied to activities that constrain production throughput, such as time required for makereadies (machine changeovers) and net machine speeds. It can, of course, be applied to other activities, as well. Isn't this SPC (Statistical Process Control)? No, not as we usually think of that system. We're not measuring properties of physical products but, instead, "activities" that consume time and materials. We're adapting a technique from CLT and SPC for print production needs.