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Choose a specific distinction
Use a pair such as conditional versus joint probability, sample versus probability-model variance, or NPV versus an undiscounted cash-flow sum. The task is to choose the correct method before calculating. This is an original practice design rather than a universal prescription for how often to mix topics.
Use prompts with different conditions
| Task | Required distinction |
|---|---|
| Dispersion of observed active returns | Sample statistic and observation interval |
| Risk of a finite scenario distribution | Supplied probability weights and model mean |
| Share within an observed event | Positive conditioning denominator |
| Overlap across the whole model | Joint probability |
Write a short justification
Before substituting numbers, identify the quantity requested and the condition that selects the method. If you cannot state that condition, consult the reference and revise the explanation.
Review method selection separately from arithmetic
A correctly executed wrong method needs a different correction from a wrong multiplication inside the right method. Keep the two records separate so later practice addresses the actual difficulty.