IMC 2008
contestants 283 · problems 12 (6+6) · scale 0–20 · per-problem yesPer-problem difficulty
Day 1
Day 2
Difficulty vs discrimination
Each dot is one problem. X — how many solved it (scored ≥ 8 of 10); Y — discrimination, i.e. how well the problem told strong contestants from weak ones (score-vs-total correlation).
A good problem sits high and away from the edges. Bottom-left dots separated nobody — almost everyone failed them the same way.
Problem statistics
Same data as the Day 1 / Day 2 charts above. Add diploma cohorts to compare winners against the field.
| # | difficulty | all | disc | topics | ||||
|---|---|---|---|---|---|---|---|---|
| avg | solved | near-0 | ||||||
| Day 1 | ||||||||
| P1 | medium | 5.4 | 48% | 40% | 0.42 | functional equationsreal analysis | ||
| P2 | medium | 4.4 | 36% | 48% | 0.63 | linear algebrapolynomials | ||
| P3 | medium | 4.7 | 32% | 26% | 0.64 | number theorypolynomials | ||
| P4 | very hard | 1.4 | 5% | 72% | 0.45 | combinatorics | ||
| P5 | killer | 0.1 | 1% | 98% | 0.22 | group theory | ||
| P6 | very hard | 1.3 | 11% | 82% | 0.47 | combinatorics | ||
| Day 2 | ||||||||
| P7 | easy | 6.1 | 54% | 22% | 0.56 | polynomialsnumber theory | ||
| P8 | hard | 2.9 | 25% | 69% | 0.46 | geometry | ||
| P9 | easy | 7.2 | 65% | 20% | 0.47 | number theory | ||
| P10 | easy | 5.5 | 55% | 44% | 0.48 | polynomialsnumber theory | ||
| P11 | very hard | 0.8 | 7% | 90% | 0.43 | linear algebranumber theory | ||
| P12 | killer | 0.7 | 4% | 90% | 0.45 | linear algebratopology & metric spaces | ||
A diploma-cohort cell needs at least 5 scores, else it shows “—”. How these statistics are computed →