Do I need to install anything?

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

For First Responders · Monty Hall

Monty Hall for a lottery-odds check

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 lottery-odds check live below — adjust the inputs and watch it respond, right in your browser.

Monty Hall ProblemLive

always switch

Controls

Speed1×

Pick one of three doors; the host, who knows where the car is, opens a losing door and offers a switch. Should you? Yes — switching wins two times out of three. Your first pick is right only 1/3 of the time, so the other 2/3 of the probability collapses onto the remaining door. The simulation converges to exactly that, however stubborn intuition is.

▶ Run in Python

Data Inspector

Games0

Switch win rate0.0%

Stay win rate0.0%

Governing equation

P (win ∣ switch) = \frac{2}{3}, P (win ∣ stay) = \frac{1}{3} \Rightarrow \overset{p}{^}_{switch} = 0.0%

Reading this result: Early on the two rates jitter around 50% because the sample is tiny — let it run and the switch rate climbs toward its true 66.7%.

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

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Frequently asked questions

Is this good for first responders?: Yes — this version of "Monty Hall for a lottery-odds check" 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.