Statistics
Probability, counting, distributions, expected value and spread, Bayes' rule, the law of large numbers, the normal curve and sampling.
10 stops21 min
The lessons, in order
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Probability
measuring maybe
Chance becomes a number between 0 and 1 — and suddenly you can do arithmetic with maybe.
2min2:23
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Counting the ways
Two dice, one question: probability = ways it can happen ÷ ways anything can happen.
2min1:58
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Distributions
the shape of chance
Every outcome gets a probability; the whole picture is a distribution, and its shape tells you what to expect.
2min1:53
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Expected value
the long-run average
Each outcome times its probability, added up: what average luck pays, and how casinos price everything.
2min1:43
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Spread
when averages lie
Same average, different risk. Variance and standard deviation measure the honesty an average leaves out.
2min2:08
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Conditional probability
given that…
Information shrinks the universe before you count. Every 'given' redraws the odds.
2min2:12
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Bayes
updating your beliefs
Belief before, evidence, belief after — the spam-filter arithmetic of changing your mind.
2min2:23
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The law of large numbers
why the house wins
Short runs are noisy, long runs are honest. Randomness rules the next flip; arithmetic rules the next million.
2min2:15
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The normal distribution
the bell that rings everywhere
Add up many small random things and one shape appears every time. The bell curve, on purpose.
2min2:21
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Sampling
the spoonful and the soup
Measure a few, conclude about all — why a stirred spoonful beats drinking the pot, and what bias breaks.
2min1:59