Create a Random Sample
A population is the whole group. A sample is a smaller part of it. Drag 5 random fish from the lake into your sample bucket.
Larger Samples are Better
The true population of this city loves pizza exactly {{s2.truePercent}}% of the time. Slide to increase your sample size and watch the sample average stabilize.
Small sample: Wildly inaccurate! Medium sample: Getting closer... Large sample: Highly representative!
Making an Inference
You surveyed {{s3.sampleSize}} students, and {{s3.sampleCount}} ride the bus. Use this ratio to estimate how many ride the bus in the whole school of {{s3.popSize}}.
Each block = 5 students
Center and Spread
Both classes have the same center (median). Tap the class that has a smaller spread (more consistent scores).
Class A
Class B
Data Master!
You know how to build a sample, why size matters, how to estimate, and how to read spread.