MATH 1F92 Chapter Notes - Chapter 1: Multistage Sampling, Simple Random Sample, Stratified Sampling
18 Sep 2016
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Stratified sample: obtained by separating the population into non-overlapping groups called strata and then obtaining a simple random sample from each stratum: the individuals within each stratum should be should be homogeneous (or similar) in some way. Stratum is singular while strata is plural the word strata means divisions: example: congress was considering a bill to abolish estate taxes. To determine the opinion of her constituency, a senator asks a pollster to conduct a survey within her state . The main criteria of stratified sampling is that each group (stratum) must have a common attribute that results in the individuals being similar within the stratum. Systematic sample: obtained by selecting every k th individual from the population. The first individual selected corresponds to a random number between 1 and k: a sampling technique not requiring a frame (a list of individuals in the population)
