For K-12 Students · Confidence Intervals
Confidence Intervals for a hypothesis test
Built for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework. Simulate a hypothesis test live below — adjust the inputs and watch it respond, right in your browser.
Confidence IntervalsLive
what 95% really means
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A confidence interval is often misread. It does not mean the true value has a 95% chance of being in one interval — it means that if you repeated the experiment many times, about 95% of the intervals would contain the true mean. The red intervals here are the unlucky ones that miss it.
Data Inspector
Confidence level95%
Observed coverage0%
Intervals shown50
Governing equation
Reading this result: About 0% of these 50 intervals captured the true mean — close to the 95% you asked for. Raising n from 30 tightens each interval (SE = σ/√n) but does not change that hit rate: the confidence level, not the sample size, sets how often you are right.
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Frequently asked questions
- Is this good for k-12 students?
- Yes — this version of "Confidence Intervals for a hypothesis test" is framed for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework.
- Do I need to install anything?
- No. It runs in any modern browser, free, with no account required.