1. Chapter 12 part 2
Types of bias

2. If multiple methods are used, we refer to it as a multistage sample.
Recap of sampling methods:
Simple Random Sample (SRS)
Stratified
Cluster
Systematic
Convenience
If multiple methods are used, we refer to it as a multistage sample.

3. The Valid Survey (Read page 280)
What do I want to know?
Am I asking the right respondents?
Am I asking the right questions?
What would I do with the answers if I had them?

4. Voluntary Response Bias
A large group of individuals is invited to respond and all who do respond become part of the sample.

5. Response Bias
Avoid anything in a survey design that influences the responses.
Be careful with wording!

6. Which question is the better option?
Question 1: Should elementary school age children have to pass high-stakes tests in order to remain with their classmates?
Question 2: Should schools and students be held accountable for meeting learning goals before they advance to the next grade?
Question 2 has better wording. The first question has response bias.

7. Nonresponse Bias
This happens when a large fraction of those sampled fails to respond. The few respondents are not likely to be representative of the population.

8. Undercoverage
This type of bias occurs when part of the population has less representation in a sample than the other parts of the population.

9. Today’s Assignment:
Practice Quiz
Add to HW: page 289 #22, 25-28
Homework Quiz next Friday