Probability & statistics Introduction
Distributions
Describe how probability is spread across outcomes.
Before this
The intuition
A distribution specifies the probabilities of possible values. It describes the whole pattern of uncertainty, rather than a single event.
A concrete example
A Bernoulli distribution models an outcome that is 1 with probability p and 0 with probability 1 − p. At p = 0.7, its expected value is 0.7.
What to remember
The expected value is a probability-weighted average; it need not be a possible individual outcome.
Check your understanding
Can one Bernoulli trial return 0.7?
Reveal explanation
No. A trial returns 0 or 1; 0.7 can be its expected value.