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Have the mean and σ already? Get Cp, Cpk, Pp, Ppk, centering k and expected PPM on each side, with a live curve.

A₂, A₃, d₂, d₃, c₄, D₃, D₄, B₃, B₄ for n = 2–25, plus an X̄-R / X̄-S limits calculator.

Paste raw data and spec limits. Estimates within and overall σ for you, with the sigma method shown.

Three questions to the right chart (I-MR, X̄-R, X̄-S, p, np, c, u), with the reason.

Main effects and interactions from a two-level factorial table.

z-table lookups and tail areas, both directions.

Series and parallel system reliability, with exponential MTTF.

Sample size for a mean, a proportion, or a test with chosen alpha and power.

Guides

Free CQE guides
Cpk vs Ppk
Choosing a control chart
Type I vs Type II error
Gage R&R explained
FMEA: RPN vs Action Priority
AQL and acceptance sampling
Full vs fractional factorial DOE
Which hypothesis test to use
Bathtub curve and MTBF

Free printable CQE formula sheet · How we check every question

Studying for the CQE?

Try 5 free practice questions with an explanation for every wrong answer.