Honors Stats Sampling & Bias

Random Sampling

Sampling Technique; choosing individuals at random in a way that isn’t planned or based on favorites, it’s random but not as strict as SRS

Stratified Random Sampling

Sampling Technique; dividing people into groups first, then picking some from each group randomly (all subgroups of a population are represented in a sample). (homogeneous)

Systematic Sampling

Sampling Technique; picking individuals in a pattern instead of randomly (suppose you want to inspect bags of chips coming from a factory. A systematic sample would involve inspecting for example every 10th bag coming off the factory, starting at some random spot)

Simple Random Sampling (SRS)

Sampling Technique; a sample in which every individual has an equal chance of being selected for the sample (like picking names from a hat) can use a random number table or random number generator to select your samples 

Convenience Sampling

Sampling Technique (BUT NOT A GOOD ONE); involved choosing the most convenient individuals from the population of your sample. Leads to undercoverage bias

Voluntary Response Sample

Sampling Technique (BUT NOT A GOOD ONE); consists of people who choose to be part of a sample by responding to a general appeal

Cluster Sampling

Sampling Technique; splits the population into representative clusters. Then randomly selects one or a few of the clusters and performs a census (entire pop.) within each clusters. Basically picking whole groups instead of picking individual people. (heterogeneous)

Multistage Sampling Design

Sampling Technique; A sample method that combines several different methods of sampling techniques 

Undercoverage Bias

A type of sampling bias; occurs when a survey leaves out some groups of people and the findings aren’t representative of a population because they didn’t get the chance to answer

Nonresponse Bias

A type of sampling bias; occurs when some people don’t answer a survey, and the people who did answer are different from the ones who didn’t

Wording of Question Bias

A type of sampling bias; when a question is asked in a way that makes people more likely to answer in a certain way

Sampling Frame

a complete and accessible list of all the individuals or elements within a target population from which a sample is drawn (a list of every member in the entire population/list of everyone you could possibly pick for your survey).

Population

An entire group of individuals that a study is interested in

Census 

When you collect data on every individual in the population

Sample

A subset of individuals from a population

Voluntary Response Bias

A type of sampling bias; occurs when a sample is composed of volunteers who may differ from individuals who don’t choose to volunteer

Self-reported Response Bias (Response Bias)

A type of sampling bias; when individuals inaccurately report things about themselves (e.g. biased in a way that maybe they think more highly or low of themselves)

Strata (Stratified Random Sampling)

A group of individuals who share something in common