Flashcards in Ch9Research Deck (15):
How is a 'population' defined?
the total group of interest
How is a 'sample' defined?
a subgroup of the group of interest
What is 'sampling'?
the procedure by which a sample of units or elements is selected from a population
Who is the 'target population'?
the group to whom researchers hope to generalize their findings
Who is the 'accessible population'?
the group of potential research participants who are actually available for a given study
What are the four types of characteristics that define populations? Which characteristics define the target population? The accessible population?
clinical, demographic, geographic, and temporal; clinical and demographic define the target population, geographical and temporal define the accessible population
What are the four types of probability sampling?
simple random sampling, systematic sampling, stratified sampling, and cluster sampling
What are the three types of nonprobability sampling?
samples of convenience, snowball sampling, and purposive sampling
What is the goal of group assignment?
to create groups that are equally representative of the entire sample; secondary goal is to develop groups of equal size
What are some of the methods used for assignment to groups?
random assignment by individual, random assignment by block, systematic assignment, matched assignment, consecutive assignment
What is ensured by the best assignment method?
group sizes are equal, group characteristics are similar, and group characteristics approximate the overall sample characteristics
What is the general principle of sample size?
larger samples tend to be more representative of their parent populations than smaller samples
What is assignment?
Process by which participants in sample are assigned to groups
What is sampling error?
It refers to the fact that vagaries of chance will nearly always ensure that one sample will differ from another, even if the two samples are drawn from the exact same target population in the same random way