This document discusses key concepts in sampling design and procedures. It covers reasons for sampling such as pragmatic and cost reasons. It also discusses defining the target population and sampling frame. The document contrasts probability sampling techniques like simple random sampling, systematic sampling, and stratified sampling with non-probability techniques like convenience sampling and snowball sampling. It discusses factors to consider in determining sample size such as variance, desired confidence level and interval. Sample size formulas for estimating means and proportions are also provided.