7th Grade · Statistics & Probability
Sample Statistic
7.SP.A.2
Definition
A numerical value calculated from sample data, used to estimate the corresponding population parameter. Common statistics: x̄ (sample mean) and p̂ (sample proportion). Changes from sample to sample.
Examples
- Sample of 30 students: sample mean x̄ = 1,920 ÷ 30 = 64 inches.
- Use x̄ to estimate μ, and p̂ to estimate p.
Key rule
A sample statistic is what we calculate; a population parameter is what we estimate.
Memory hook
Calculated from the sample, used to guess the population.