1. The Practice of Statistics
Daniel S. Yates
The Practice of Statistics
Third Edition
Chapter 5:
Producing Data
Copyright © 2008 by W. H. Freeman & Company

2. Sampling Frame
The list of individuals from which a sample is actually selected. The sampling frame should include all individuals from the population.

3. 4 Potential Sources of Bias (even with a well chosen sample)
Undercoverage
Nonresponse
Response
Wording of Questions

5. Response Bias Response bias occurs when sample results are inaccurate.
Possible causes are:
behavior of the respondent or of the interviewer
reluctance to admit illegal or unpopular behavior
faulty memory
race or sex of the interviewer

7. Wording of Questions
is the most important influence on the answers given to a sample survey.
Confusing or leading questions can introduce strong bias, and even minor changes in wording can change a survey’s outcome.
Questions should be clear and neutral (not slanted toward one of the answer choices).

8. Can you believe the results?
Insist on knowing the exact questions asked, the rate of nonresponse, and the date and method of the survey before you trust a poll result.

9. Inference about Population
Sample results will vary while population parameters do not. Larger random samples give more precise results than smaller samples.