What’s inside:
- Part 1 ยท Sample City โ 100 hidden residents in a 10ร10 grid. Survey 10 at RANDOM reveals a fair sample and scales it up (“6 of 10 โ โ60% of the city”), with a running history of estimates so students see sampling variation (50%, 70%, 60%…). The โ ๏ธ ONE street only button surveys Elm St. โ where neighbors think alike โ and overshoots every time, making bias tangible. Reveal the whole city shows the true 60% and compares it against both sampling methods.
- Part 2 ยท The Carnival Games โ four rotating booths (double-heads, spin-&-flip, at-least-one-head, double-green). Students commit to one of three probabilities, then the booth opens its full sample space as a table with winning cells in gold โ feedback specifically names the collapsed-list trap (HH/”one of each”/TT) and the adding trap (โ + ยฝ = โ ). After the reveal, “Play it 200 times โถ” runs a live simulation showing experimental probability wobbling around theory.
- Part 3 ยท Behind the Booths โ ๐ Inference Machine (checks randomness first, finds the sample proportion, scales up with the “not k, and not the percent” warning, and reports honestly with wobble language), โ๏ธ Data Duel (three preset matchups engineered to separate the concepts: A-better-and-steadier, B-clearly-better, and same-center-different-consistency โ comparing mean and range with plain-language verdicts), and ๐ณ Sample Space Builder (three two-step experiments: count each step, multiply the counts, list every outcome, extract P).
- Part 4 ยท Quiz โ 10 questions across sampling design, inference scaling, sample variation, center-and-spread comparison, the probability scale, the 50/50 fallacy, the gambler’s fallacy, compound sample spaces, AND-multiplication, and experimental vs. theoretical.
Misconception coverage summary: Questions 1โ3 target sampling and inference errors โ trusting friends, the pizza line, or a single team as a sample, reporting the raw sample count or the percent as the population answer instead of scaling, and misreading normal sample-to-sample variation as error or false precision. Question 4 targets comparison traps: judging a group by its single best score and believing more varied scores mean more consistency. Questions 5โ7 and 10 target probability-model errors: probabilities above 1, the “two outcomes = 50/50” fallacy, the gambler’s fallacy in both “due” and “hot streak” forms, and over-reading small experiments as loaded dice or permanently changed probabilities. Questions 8โ9 target compound-event traps โ the three-outcome collapsed sample space for two coins and adding instead of multiplying for AND events.

