Main Points of Chapter 7

1. Know the Literary Digest mistake.

2. Understand the difference between "nonprobability" and "probabiltiy" sampling.

3. Be able to describe several nonprobability samples (e.g. quota, snowball, etc.).

4. Understand the difference between population, sampling frame and sample.

5. Understand confidence intervals in the context of sample size.

6. Know the four types of probability samples discussed in class.

7. Especially know the proportionate stratified sampling