Math
Sampling distribution of a mean.
Definition
The probability distribution of all possible sample means from samples of a fixed size drawn from a population. By the Central Limit Theorem, this distribution is approximately normal for large sample sizes, centered at the population mean with standard deviation σ/√n.
Examples
Real-world.
- 1 Taking many random samples of 30 students' test scores and plotting the average of each sample
- 2 Measuring the mean weight of 50 apples repeatedly from a large orchard to see how the average varies
Key Fact
Standard error = σ / √n