# Topic C7 — Sampling

## Sampling methods

### Simple random sampling

• All observation have the same probability of being sampled

### Stratified sampling

• Dividing dataset in mutually exclusive + collectively exhaustive stratas.
• Sample x% of each strata
• precision
• every strata represented

### Cluster sampling

• Dividing dataset in mutually exclusive + collectively exhaustive clusters
• Randomly select some clusters
Will converge to the mean of pop $\mu$
Standard error of sample mean $\frac{\sigma}{\sqrt{n}}$