AtlasFoundations · start here
Chance and probability
- Fractions, proportions, percentages and rounding
- Chance and probability
Fig. 1
Ten rats allocated by fair coin tosses (heads per toss of 10 coins) and the three-ball bag (red balls per run of draws)
Fig. 1. Bars for 0 to 10 heads, empty until the 10 coins are tossed.
- Tosses
- 0
- Heads so far
- 0 of 0
- Share of heads
- —
Distribution Lab · First look
Level 1 · First look · Foundations (ext)
Describe chance as a share from 0 (never) to 1 (certain).
Express a chance as a number from 0 to 1, read it as a long-run proportion, and multiply chances for independent events.
ext A Foundations primer: written for beginners, not from the slides.
Chance scale (the step you are on)
Never (rolling a 7 on one die) is 0, even (heads) is ½, certain (sunrise) is 1.
The dial runs from 0 (never, like rolling a 7 on one die) to 1 (certain, like sunrise); a fair coin’s heads sits at the red ½. Toss the 10 coins: heads so far, 0 of 0.