STAT 100 Lecture Notes - Lecture 3: Selection Bias, Response Bias, Simple Random Sample
Document Summary
Non-probability methods: a sampling technique where the samples are gathered in a process that does not give all the individuals in the population equal chances of being selected. (results can only be inferred to sample) Probability methods: any method of sampling that utilizes some form of random selection. The different units in the population have an equal chance of being selected. (results can be extended/inferred to population represented by sample) Purpose is to attain a sample that represents some population of interest. Simple random sample: every subject in population has an equal chance of being selected. Stratified random sample: population is split into groups or strata, then a random sample is taken from each strate. Cluster sampling: stratified, but the sampling is done by taking a cluster of subjects. Ex: split classroom into 3 sections; left, middle, and right. Ex: taking 5 boys from left section of classroom.
