S27 · interview simulation
Teach back what an 80% interval promises and how to check it
People, data and outputs in this scenario are simulated. Each stage is recorded when you commit; the reveal comes after.
- 4stages
- 25 minabout
- 0stages committed
The brief
A capacity planner (simulated) at the synthetic airline uses a baseline forecast of passengers per flight-day with an 80% interval. The forecast is the mean of the same flight's four previous same weekdays; the interval is the forecast plus or minus 1.28 times the standard deviation of that flight's 2022-2023 forecast errors (a normal approximation).
Evaluated on 2024 (6,954 flight-days), recomputed from the course database:
- Coverage of the 80% interval: 81.5% overall.
- On IST-ADB, IST-AYT and IST-FRA after the competitors' capacity step on 2024-03-01 (2,142 flight-days): 77.6%.
- On the same three routes in January and February 2024, before the step (420 flight-days): 77.4%.
- By route, the lowest are IST-AYT 76.8%, IST-ADB 77.8%, IST-ATH 77.9% and IST-FRA 78.1%; the others range from 83.0% to 85.2%.
- A 95% interval built the same way covers 96.3%, with a mean half-width of 53.9 passengers against 35.2 for the 80%.
Rule of the exercise: write your explanation before reading any feedback. The interviewer then probes twice.
Stage 1 of 4
Simulated planner: "The report says 80% interval. What is it promising me, and how would I know whether it keeps the promise?"
Explain what an 80% interval means for a single flight-day and over a year, and how you would check it. Mention what the check can and cannot tell you.