Sampling Basics
What is sampling?
The process by which research participants are selected from a population
A sampling method where each participant has an equal and random chance of being selected
What is Simple Random Sampling?
Participants are selected because they are easy to access
What is Convenience Sampling?
More likely to produce a representative sample
What is probability sampling?
Bigger sample always guarantee representativeness (True or False)
What is false?
The entire group of people targeted by the research question
What is a Target Population?
After a random starting point, every 10th person on a list is selected
What is Systematic Sampling?
Participants are hand-picked because they meet specific criteria
What is purposive sampling?
Necessary when population characteristics are unknown (i.e. people who drink Moxie)
What is non-probability sampling?
Results likely due to intervention and unlikely due to chance
What is statistical significance?
The accessible subset of the target population from which participants are recruited
What is the source population/sampling frame?
Dividing the population into subgroups and randomly sampling from each group
What is Stratified Sampling?
Current participants recruit future participants from their social network
What is Snowball Sampling?
Simpler than simple random sampling, but may introduce bias if patterns exist in the list
What is systematic sampling?
Large samples are better able to reduce this
What is the effect of chance?
Individuals who were invited to participate in the sampling frame
What is the sample population?
Randomly selecting geographic regions and sampling within them
What is cluster sampling?
Participants are divided into characteristic groups but selected without randomization
What is Quota Sampling?
Often used for large population spread across geographic regions
What is cluster sampling?
Small samples must show this in order to achieve statistical significance
What is large effect size?
Sample individuals who consent and actually participate in the study
What is the study population?
When probability sampling is used and distribution of characteristics matches the population
What is external validity (or generalizability)
This type of sampling lacks external validity because the distribution of characteristics does not match the population
What is non-probability sampling?
Similar to stratified sampling but without randomization
What is quota sampling?
A study with 20 participants shows dramatic improvement after intervention. Why might this not be statistically significant?
What is the sample size is too small to mitigate chance variation?