Walter A. Shewhart: Doing

“The definition of random in terms of a physical operation is notoriously without effect on the mathematical operations of statistical theory because so far as these mathematical operations are concerned random is purely and simply an undefined term. The formal and abstract mathematical theory has an independent and sometimes lonely existence of its own. But when an undefined mathematical term such as random is given a definite operational meaning in physical terms, it takes on empirical and practical significance. Every mathematical theorem involving this mathematically undefined concept can then be given the following predictive form: If you do so and so, then such and such will happen.”

Walter A. Shewhart

[Shewhart, Walter A., Deming, William E., Statistical Method from the Viewpoint of Quality Control, The Graduate School, The Department of Agriculture, 1939, 18]
Economic Control of Quality of Manufactured Product,1931

“Postulate 1. All chance systems of causes are not alike in the sense that they enable us to predict the future in terms of the past.
Postulate 2. Constant systems of chance causes do exist in nature.
Postulate 3. Assignable causes of variation may be found and eliminated.”

Walter A. Shewhart

Source: Economic Control of Quality of Manufactured Product,1931, p. 8

“Broadly speaking, the object of industry is to set up economic ways and means of satisfying human wants and in so doing to reduce everything possible to routines requiring a minimum amount of human effort.”

Walter A. Shewhart

Source: Economic Control of Quality of Manufactured Product,1931, p. vii