Glossary · Phase 2 · Math, when you need it
Bootstrap
Estimating uncertainty by resampling your own data, with replacement, many times and seeing how much the answer moves.
Try it now
Each run is 1,000 experiments. Each one measures the conversion rate from n visitors. Raise the visitors per experiment and watch the spread of measured rates shrink.
Learn it properly
Samples and confidence · Estimate from a sample and say how sure you are. About 30 minutes.
Other terms from the same lesson
- confidence interval: A range that probably contains the true value, given the data you sampled.
- margin of error: The plus-or-minus around an estimate, such as 3.2% ± 0.8%. It is usually about two standard errors.
- resample: Draw a new sample from your data, picking rows at random with replacement, to mimic collecting fresh data.
- standard error: How much an estimate from a sample would wobble if you took a fresh sample. Bigger samples give smaller standard errors.
Never trained an AI?
Teach a small one to write, right in your browser. It takes about 20 seconds and needs no account.