As we learned last month, the precision to tolerance ratio is a trigonometric function multiplied by a scalar constant. This means that it should never be interpreted as a proportion or percentage. Yet the simple P/T ratio is being used, and misunderstood, all over the world. So how can we properly...
The keys to effective process behavior charts are rational sampling and rational subgrouping. As implied by the word rational, we must use our knowledge of the context to collect and organize data in a way that answers the interesting questions. This column will show the role that sample frequency...
Continuing our thinking about ways for data leaders to save money during a recession, this article drills into saving on your data usage. Following my last post reminiscing on the lessons I learned during past recessions, the early environmentalist slogan “reduce, reuse, recycle” has stayed in my...
As the foundations of modern science were being laid, the need for a model for the uncertainty in a measurement became apparent. Here we look at the development of the theory of measurement error and discover its consequences.
The problem may be expressed as follows: Repeated measurements of one...
