Probability Paradoxes in Spreadsheets: Monty Hall, Birthdays, Simpson's & Base Rates

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• List all nine car/pick combinations of the Monty Hall game, mark when staying and when switching wins, and compute both winning chances, also for a 10-door version.
• Build the birthday table for groups of 1 to 40 people step by step with PRODUCT, find the group size where a shared birthday becomes more likely than not and chart the S-curve.
• Compare two basketball players' shooting percentages by shot type and overall, see the ranking flip, and fix the comparison by giving both the same shot mix.
• Screen 100,000 people for a rare condition with a "99% accurate" test, count true and false positives as natural frequencies and see why most positives are false, and what a second test changes.
• Show that a coin has no memory (the 6th flip after five heads is still 50/50) and count how likely a streak of five heads is somewhere in 50 flips: more likely than not.
• Solve two classic conditional-probability puzzles by listing equally likely cases and counting with COUNTIFS: the gold coin in Bertrand’s box and the two-child family.
• Price the St. Petersburg coin game: every row adds $1 of expected value, a casino cap cuts it to about $20, and log utility values it at only about $4.
• Compare test and retest scores of twelve apprentices: the top three drop, the bottom three rise, and a regression line predicts a retest score closer to the average.