7th Grade · Statistics & Probability
Population Parameter
7.SP.A.2
Definition
A number that describes a characteristic of the entire population. Usually unknown; estimated using sample statistics. Symbols: μ (mean), p (proportion), σ (standard deviation).
Examples
- True mean height μ = 63.8 inches for all 500 students (usually unknown).
- Sample mean x̄ = 64 in estimates the population mean μ.
Key rule
We usually don't know the parameter — the population is too large to measure everyone.
Memory hook
The true value for everyone, which we estimate from a sample.