How many draws to finish the set?
Collecting every equally likely type has a long tail because duplicates become common near completion.
Inside this model
Independent draws are uniform across the selected types. Exact expected draws to collect k types equal N times the sum of 1/(N-i) for i from zero to k-1. A seeded run shows one possible path.
Out in the world
A practical use
Planning how many random packs may be needed to complete a collection.
A useful lens. Not a universal law.
- Real items may have different rarity and draws may not be independent.
Further reading
Explore the original research or the teaching reference behind this experiment.
Eric Weisstein — Coupon Collector's Problem ↗