1. Producing Data
Chapter 5

2. Observational Study
Observes individuals and measures variables of interest but does not attempt to influence the responses

3. Experiment
Deliberately imposes some treatment on individuals in order to observe their responses

4. Statistical Inference
Answers specific questions with a known degree of confidence

5. Designing Samples
Section 5.1

6. Population
The entire group of individuals that we want information about

7. Sample
Part of the population that we actually examine in order to gather information

8. Sampling
Involves studying a part in order to gain information about the whole

9. Census
Attempts to contact every individual in the entire population

10. Sample Design
Refers to the method used to choose the sample from the population

11. Types of Sample Design

12. Voluntary Response Sample
Consists of people who choose themselves by responding to a general appeal
Usually bias

13. Convenience Sampling
Chooses the best individuals easiest to reach

14. Bias
Systematically favors certain outcomes

15. Simple Random Sample
Each individual in a population has an equal chance to be selected into a sample

16. Table of Random Digits
Long string of digits 0 thru 9 with 2 properties:
Each entry in the table is equally likely to be any of the 10 digits
Entries are independent of each other

17. Probability Sample A sample chosen by chance
Need to know what samples are possible and what chance, or probability, each possible sample has

18. Note:
The use of chance to select the sample is the essential principle of statistical sampling

19. Stratified Random Sample
Divide the population into groups of similar individuals, strata
Choose a separate SRS in each stratum
Combine the SRSs to form the full sample

20. Undercoverage
Occurs when some groups in the population are left out of the process of choosing the sample

21. Cautions About Sample Surveys

22. Nonresponse
Occurs when an individual chosen for the sample cannot be contacted or does not cooperate

23. Wording of Questions
Most important influence on the answers given to a sample survey

24. Note:
Large random samples give more accurate results than smaller random samples

25. Practice Problems
pg. 285 #