Check your work: Repair a fictional delivery estimate until a reader can teach it back

Staged checking material

Answer key

1. Arithmetic: 56/80 = 70% = 7 in 10 in-window; 12/80 = 15% early and 12/80 = 15% late.
2. Uncertainty is MIXED: which individual delivery arrives when varies (aleatory), while the new backlog creates uncertainty about whether the historical frequency remains representative (epistemic).
3. Model message: ‘In 80 similar deliveries, 56 arrived Tuesday–Thursday: 70%, about 7 in 10. Twelve arrived earlier and 12 later. A new backlog may make that history less reliable. No action now; if absent Thursday at 17:00, the coordinator asks for an update.’
4. Model teach-back: ‘About 7 in 10 similar boxes arrived in-window; some were early or late, backlog may shift this, and the check occurs if absent Thursday at 17:00.’
5. A full comparison preserves the learner's original wording and score, identifies each repaired field and records any remaining gap after the model; reassurance and trust are not checklist points.

Scoring rule

Award 1 point for each of the six explicit message elements, 1 for a correct MIXED uncertainty classification and 1 for a teach-back that preserves estimate, uncertainty and trigger: 8 total. Baseline and repair remain separate. Opening or copying the staged model before locking the repair invalidates the baseline comparison.

Authority boundary: A governed step-by-step lesson may be completed independently inside its stated limits.