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Stats Ch 9
Term | Definition |
---|---|
Population | The entire group of individuals or instances about whom we hope to learn. |
Sample | A representative subset of the population. |
Sample Survey | A study that asks questions of a sample drawn from some population in the hope of learning something about the entire population. |
Bias | Any systematic failure of a sampling method to represent the population. |
Randomization | The best defense against bias where each individual is given a fair, random chance of selection. |
Sample Size | The number of individuals in a sample. |
Census | A sample that consists of the entire population. |
Population Parameter | A numerical attribute of a model for a population. |
Sample Statistic | Numerical summary calculated from sample data. |
Representative | A sample where the statistics computed accurately reflect the corresponding population parameters. |
Simple Random Sample | A sample in which every person has an equal probability of being selected as part of the sample. |
Sampling Frame | A list of individuals from whom the sample is drawn. |
Sampling Variability | The natural tendency of randomly drawn samples to differ from one another. |
Stratified Random Sample | A sample in which the population is divided into several subgroups that share a common characteristic, then a random sample is taken on each subgroup. |
Cluster Sample | A sample in which entire groups are selected at random, then a census is administered on that subgroup. |
Multistage Sample | A sample that combines several sampling techniques. |
Systematic Sample | A sample in which individuals are drawn from the population according to some nonrandom algorithm. |
Pilot Study | A small trial run of a survey to check whether the questions are clear and unbiased. |
Voluntary Response Bias | Bias introduced when individuals decide on their own that they want to be part of a sample. |
Convenience Sample | A sample consisting of individuals who are readily available. |
Undercoverage | Bias introduced when a portion of the population has less representation in the sample than the population. |
Nonresponse Bias | Bias introduced when a large portion of the sample simply do not participate. |
Response Bias | Bias created when anything in a survey design influences responses. |