Chance Lab
● Make chance visible

What happens when
random things team up?

Pick dice, coins, or number shapes. Combine them, run thousands of tiny experiments, and watch a pattern appear.

Build an experiment
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Start with a story

Quick experiments

Choose one, then change anything you like.

Your turn

Build your experiment

The computer repeats your idea many times. More repeats make a steadier picture.

1

Choose random things

You can mix different kinds together.

2

Write the team-up formula

Each number means the matching distribution above.

Insert
Quick build

Use +, −, ×, ÷ and parentheses. Reusing a number reuses the same sampled value.

Ready to calculate

3

How many experiments?

This is different from the 3 values combined each time.

50,000repeats
Distribution guide

Seven ways randomness can look.

A distribution describes the possible results and how chance is spread between them. Discrete distributions have separated outcomes; continuous distributions cover a whole number range.

Discrete

Fair die

A fixed set of whole-number results. Every side is equally likely, so a six-sided die gives each number a 1 in 6 chance.

Controls
Choose the number of sides.
Try it: board-game rolls.
Discrete

Coin

A two-result experiment: success or not success. The two chances always add to 100%.

Controls
Choose the chance of heads.
Try it: heads or tails, yes or no.
Discrete

Success counter

Also called a binomial distribution. It counts how many successes happen across several independent tries.

Controls
Choose the number of tries and success chance.
Try it: how many of 10 shots go in?
Discrete

My own outcomes

Create any list of possible values. Weights let some values appear more often than others.

Controls
Enter value:weight pairs.
Try it: prizes in a spinner game.
Continuous

Even range

Also called a uniform distribution. Equal-sized parts of the range have equal chances.

Controls
Choose a minimum and maximum.
Try it: a random point along a ruler.
Continuous

Bell curve

Also called a normal distribution. Values gather around the center, while far-away values become rarer.

Controls
Choose the center and spread.
Try it: measurement differences.
Continuous

Triangle

A bounded range with one most likely point. Chances rise toward that point, then fall away.

Controls
Choose minimum, most likely, and maximum.
Try it: estimating how long a task may take.