Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For First Responders · Survey Analysis

Survey Analysis for a p-value

Built for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field. Simulate a p-value live below — adjust the inputs and watch it respond, right in your browser.

Confidence Interval

open full solver →

Confidence IntervalsLive

what 95% really means

Controls

Presets

Sample size n

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.

▶ Run in Python

Data Inspector

Confidence level95%

Observed coverage0%

Intervals shown50

Governing equation

\overset{x}{ˉ} \pm z \frac{σ}{n} = 50 \pm 1.96 \cdot \frac{10}{30}

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.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

↓

Distributions

open full solver →

Probability DistributionsLive

PDF / PMF explorer

Controls

Presets

Mean μ

Std dev σ

▶ Run in Python

Data Inspector

Distributionnormal

Mean0.000

Variance1.000

Std dev1.000

Governing equation

f (x) = \frac{1}{2 π 1.00} e^{- \frac{( x - 0 ) ^{2}}{2 \cdot 1.00}}

Reading this result: The mean μ only slides the bell sideways while σ sets its width — variance is σ² = 1.00, so doubling σ quadruples the spread.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

or unlock everything with Pro →

Also for:Students Researchers Educators Engineers Hobbyists & Makers K-12 Students General version →

More with Survey Analysis

Survey Analysis for an A/B test Survey Analysis for a survey sample Survey Analysis for a poll margin Survey Analysis for a quality-control chart Survey Analysis for a clinical trial Survey Analysis for a customer churn Survey Analysis for a click-through rate Survey Analysis for an exam-score curve

Frequently asked questions

Is this good for first responders?: Yes — this version of "Survey Analysis for a p-value" is framed for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.