Sampling is a 4 step process:
1. Define the target population (who)
--> total grp of indiv from which sample might be drawn
2. Identify the sampling frame (how to find?)
--> one that overlaps w the target population and has no systematic biases (error due to non-random sample)
--> accessibility bias, self-selection bias, termination bias
3. Select the sampling plan (how to select?)
--> probability: simple random, stratified random
--> non-probability: convenience, judgmental, quota, snowball [gd: cost effective, efficient] [bad: not representative, cannot be generalised]
4. Determine sample size (how many?)