Stage 2 · Lesson 2 of 8
Distributions you will meet
A distribution describes how often each value of a random quantity turns up. A few shapes cover most data work. The , the bell curve, appears when many small effects add up, such as measurement error or heights.
The binomial counts successes out of a fixed number of tries, such as conversions out of 1,000 visitors. The Poisson counts events in a period, such as support tickets per hour. Skewed shapes, with a long tail on one side, describe money and durations.
Recognising the shape tells you which summaries, tests and models fit. Plot a histogram of each important column before you assume anything.
Common trapassuming everything is normal, when counts, prices and waiting times are usually skewed and can never go below zero.
A question to check yourself, an AI practice session and 1 cheat sheet entry come with the full roadmap. Unlock
Resources for this stage
Start with· follow one of these
- VideoFreeStatQuest with Josh Starmer
StatQuest · Beginner
Free: short, clear videos on each concept, from the normal distribution to p-values and power
- CourseFreeKhan Academy Statistics and Probability
Khan Academy · Beginner
Free: the probability, sampling distributions, confidence intervals and significance tests units, with practice
Practise
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Interactive visuals for probability, distributions, inference and regression: play with each one