Chapter 7 Flashcards
(16 cards)
differ between a biased or unbiased sample
If each member of the population has an equal chance of being selected then it is an unbiased sample
Name two ways of getting a biased sample
Convenience sampling and self selection
What is meant by probability sampling
When each member of the population has an equal chance of being selected despite willingness or convenience. This is the opposite to nonprobability sampling.
What is simple random sampling?
When every member of the population is equally likely to be selected.
What is cluster sampling?
When people are already divided into arbitrary groups , certain groups are randomly selected and every member within this group is used.
Describe multistage sampling
When a random sample of clusters are selected and then a random sample of participants within those clusters is selected.
Explain stratified random sampling
When the researcher purposefully selects particular demographic categories and then randomly selects participants within those categories (age, race etc.)
What is meant by oversampling?
When the researcher intentionally over represents one or more groups.
What is systematic sampling?
When researchers randomly pick numbers n and then select every nth sample
What is meant by weighting?
When a final sample contains fewer members of a subgroup than it should the data can be adjusted so that responses from members of underrated categories count more.
When is random assignment used?
Experiments in assigning participants
What is purposive sampling?
When a researcher only recruits certain kinds of people they intend to study. (not random)
What is snowball sampling?
When participants are asked to recommend a few acquaintances for the study (not random)
What is quota sampling?
When a researcher identifies subsets of the population of interest and then sets a target number for each category. (80 asians, 80 latinos etc.) (not random)
When is a large sample size important
When a phenomenon is rare, to locate enough instances of that phenomenon for valid statistical analysis.
What is the most people polls usually attempt to survey?
2,000
