Transforming the Exponential for SPC Applications

Abstract

The long-tailed, positively skewed exponential distribution can be made into an almost symmetric distribution by taking the fourth root of the data. The transformed data can then be plotted conveniently on an individuals chart, an exponentially weighted moving average chart, or a cumulative sum chart for statistical process control (SPC). The log transformation of the exponential distribution, used for proper analysis of variance calculations, does stabilize the variance, but produces a very negatively skewed distribution that is not suitable for SPC applications. The observations for the fourth root can be easily calculated with a pocket calculator by depressing the square root key twice.

Cite this work

No public copy is stored for this record, so only the metadata is cited.

Stored only when both papers are in the corpus — 38 citations exist upstream.

Papers that cite the same references — the relational fallback while embeddings are still backfilling.