This Monty Hall-style lab teaches the probability shift without assuming the concept is already familiar. Make an initial choice, remove a known miss, then run repeated trials in real time to watch the keep-versus-switch results settle into their long-run pattern. Deeper simulation modes expand the same rule to larger starting sets and partial reveals.
What this shows
The simulator starts with a first choice, reveals information that is known to be wrong, and then compares keeping the first choice against switching after the new information arrives.
How to read it
One round can feel noisy. Repeated trials show the pattern: the original choice keeps its starting probability, while the remaining unrevealed alternative can carry more of the probability from the options you did not choose.
Why it matters
The lab is a small model for decision quality. A person can make a reasonable first choice, receive new information, and still need to update the decision instead of defending the original pick.
Limits
This is an educational probability lab. It is not a market model, investment recommendation, or proof that switching is always the right action in every real system.
Related
Compare it with Chaos Divergence Explorer and Market Intelligence Field Notes.