Learn by making
When missing is not zero
One changed value. A different answer.
Precomputed scenarios rebuilt with native Emacs/Org, AWK, GNU Make and gnuplot. Your browser selects the checked outputs; it does not run these tools.
Missing is not zero
A03 is missing (NA); A04 is a measured zero. The zero contributes to the mean. Missing and rejected observations stay in the census.
| Group | Total | Used | Missing | Rejected | Mean |
|---|---|---|---|---|---|
| A | 5 | 3 | 1 | 1 | 10.00 |
| B | 5 | 3 | 1 | 1 | 15.00 |
Inspect the input observations
| Sample | Group | Value | Status |
|---|---|---|---|
| A01 | A | 10 | valid |
| A02 | A | 20 | valid |
| A03 | A | NA | valid |
| A04 | A | 0 | valid |
| A05 | A | 100 | invalid |
| B01 | B | 5 | valid |
| B02 | B | 15 | valid |
| B03 | B | 25 | valid |
| B04 | B | NA | valid |
| B05 | B | 40 | invalid |
Input TSV · Result TSV · Execution evidence · Exact tour example ↗
A03 becomes a measured zero
Only A03 changes from NA to an observed zero. A now has four usable observations; its sum stays 30 and its mean falls to 7.50. B is unchanged.
| Group | Total | Used | Missing | Rejected | Mean |
|---|---|---|---|---|---|
| A | 5 | 4 | 0 | 1 | 7.50 |
| B | 5 | 3 | 1 | 1 | 15.00 |
Inspect the input observations
| Sample | Group | Value | Status |
|---|---|---|---|
| A01 | A | 10 | valid |
| A02 | A | 20 | valid |
| A03 | A | 0 | valid |
| A04 | A | 0 | valid |
| A05 | A | 100 | invalid |
| B01 | B | 5 | valid |
| B02 | B | 15 | valid |
| B03 | B | 25 | valid |
| B04 | B | NA | valid |
| B05 | B | 40 | invalid |
Input TSV · Result TSV · Execution evidence · Exact tour example ↗
Download executable sources & checks →
Rebuilt using 31.1 / Org 9.8.7, awk version 20200816, GNU Make 4.4.1 and gnuplot 6.0 patchlevel 6. Original baseline fixtures and an independent calculation check both scenarios.
Source: ROOT & SHAPE tour · Original study source, fixtures and figures: CC0-1.0. Publishing/bootstrap structure: CC BY 4.0. Lukas C. Bossert.