1. 1 UNIT 10: POPULATION AND SAMPLE

2. 2 Population The entire set of people, things or objects to be studied An element is a single member of the population A census is a count of all elements in a population

3. 3 Population Issues Defining the population Determining the population/sampling frame -Accurate number of elements in the population -Use of multiple sources -Use most recent sources

4. 4 Sample A subset of the population This is the group that is studied Conclusions from the sample are generalized to the population of interest A subject is a single element of the sample

5. 5 Sample and Population StatisticsParameters (Mean, Variance Estimate (Mean, Variance,Standard deviation)

6. Sampling Process of selecting an appropriate number of elements from the population Sampling may be done where: - the population is large -studying the entire population would be prohibitive in terms of cost/resources -it would be destructive to do otherwise Studying a representative sample is important - accuracy of population estimates 6

7. Sampling Designs Probability sampling - elements in the population have a known probability (chance) of being selected as sample subjects Non probability sampling -elements in the population do not have a known chance of being selected as sample subjects *Sampling designs have implications for generalizability 7

8. Probability Sampling Simple random sampling Cluster sampling Area sampling Stratified Sampling 8

9. Non-probability Sampling Convenience sampling Purposive sampling -Judgmental sampling -Quota sampling 9