01 · Purpose
Why and when to use it
Use it as a location summary when the distribution is skewed or when a resistant centre is useful.
Who takes part?
The measurement owner works with people who understand the process and the recorded data. Statistical or measurement-system decisions should involve someone able to check the assumptions and study design.
02 · Application
How to apply it
Start with an agreed measurement purpose, explicit units and trustworthy observations. Identify missing cases and assumptions before calculating.
- Check eligibility and missingness.
- Sort the numerical values.
- Find the middle value or average the central pair.
- Report units, sample size and period.
- Interpret it with spread and tails, not as a guarantee about every case.
03 · Example
A worked measurement example
Original fictional teaching example. Small datasets illustrate the method; they are not proposed as sufficient study sizes. Supplied parameters are assumptions, not estimates from a real process.
| Dataset (minutes) | Median |
|---|---|
| 2, 4, 4, 6, 9 | 4 |
| 2, 4, 6, 9 | (4 + 6) / 2 = 5 |
04 · Interpretation
What the result tells you
The five-value median of four minutes describes the centre; it does not mean all orders are packed within four minutes. A median target can conceal poor tail performance.
Completion check: A median with clear data coverage and an appropriate interpretation.
05 · Judgement
Mistakes and limitations
For ordinal categories, report a median category carefully rather than assuming arithmetic interpolation is meaningful. The median alone hides operationally important extremes.
07 · Reading
Sources and further reading
The tool list follows the accepted LeanTrainingLab overview and its reference to Six Sigma+Lean Toolset, second edition (Lunau, editor; Springer, 2013). The book chapters were not available for direct review during this build. Explanations, examples and worksheets are original teaching material. Further reading supplies professional background; local conventions are stated explicitly.