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Walter A. Shewhart is lauded as the Father of Statistical Process Control (SPC) and is perhaps best remembered for the SPC control chart. The first record of Shewhart’s control chart is found in a Bell Telephone Laboratories internal memo from May 16, 1924, making today the 100th anniversary of…
Read articleOne hundred years ago this month, Walter Shewhart wrote a memo that contained the first process behavior chart. In recognition of this centennial, this column reviews four different applications of the techniques that grew out of that memo.
The first principle for interpreting…
Read articleIn less than two months we will celebrate the 100th anniversary of the invention of the control chart, a tool most often associated with statistical process control (SPC). Considering SPC from our modern perspective made us ask, “Is SPC still relevant?”
It’s a question asked…
Read articleWhen presented with a collection of data from operations or production, many will start their analysis by computing descriptive statistics and fitting a probability model to the data. But before you do this, there’s an easy test that you need to perform.
This test will quantify…
Read articleOver the past two months we’ve considered the properties of lognormal and gamma probability models. Both of these families contain the normal distribution as a limit. To complete our survey of widely used probability models, this column will look at Weibull distributions, a family that doesn’t…
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