Calculator
Scientific calculator with statistics and 6σ mode
Overview
The scientific calculator is an integrated helper for quick computations without leaving the app. It offers three modes, each tailored to a typical Six Sigma use case.
Scientific mode: Classic calculator with basic arithmetic, powers, roots, logarithms, trigonometric functions, constants (π, e), and parentheses. Suitable for general numeric calculations.
Statistics mode: Enter a list of values; the calculator returns mean, median, standard deviation, variance, minimum, maximum, skewness, and sample size. Handy for a quick description of small datasets.
Six Sigma mode: Computes Cp and Cpk from mean, standard deviation, and lower/upper specification limits. Also converts between DPMO, sigma level, and yield.
The calculator does not replace full analysis modules — for Cpk studies with distribution fitting, control charts, or larger datasets, use the dedicated module.
Operation
- Pick a mode at the top via the tabs (Scientific / Statistics / Six Sigma).
- Enter numbers and operators with the on-screen keys or your keyboard.
- In Statistics mode, paste values separated by commas or line breaks — copy & paste from the worksheet works as well.
- In Six Sigma mode, enter specification limits, mean, and standard deviation — Cp/Cpk update immediately.
- DPMO ↔ sigma level ↔ yield: enter one of the three, the others are computed automatically.
Pitfalls
Sample vs. population standard deviation: The Statistics mode uses the sample standard deviation (divisor n−1). This is the standard for real measurement data — when comparing against other software, check which variant it uses.
Cp/Cpk without normality check: The Six Sigma mode computes without checking the distribution assumption. For non-normal data the result is misleading — verify with a probability plot or distribution fit beforehand.
DPMO is not ppm: DPMO refers to defect opportunities per unit, ppm to defects per million parts. With multiple opportunities per part the two values differ substantially.
Trigonometric input: Scientific mode expects arguments in radians unless explicitly switched to degrees. If results look wrong, check the angle mode.
No audit trail: Calculations are not stored in the project. Transfer important intermediate results to the worksheet or project charter, otherwise they are lost on close.