Problem-Solving & Data

Rates, percents, statistics and probability

Every lesson's first step is free. Your stars need an account.

1. 1Set up a proportion or unit rateLabel every rate with units, then match or cancel them10 min
2. 2Convert units by factor chainingMultiply by 1 until only the units you want are left9 min
3. 3Percent change, chains, and reverseMultiply forward, divide back, never add percents10 min
4. 4Reason about center and spreadMeans follow the total, medians follow the middle11 min
5. 5Scatterplots and best-fit modelsPredictions and slopes come from the line, not the dots10 min
6. 6Probability from tables and conditionsShrink the total to the condition, then count10 min
7. 7Sample estimates and margin of errorScale up the sample, then read the margin as a range9 min
8. 8Evaluate study design and generalizationAsk who was picked, then who picked the groups10 min