ENVS278 Study Guide - Final Guide: Categorical Variable, Control Variable, Unimodality
15 Apr 2017
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Document Summary
Defines a set of symmetric, unimodal, distributions with two parameters: mean ( ) and the standard deviation ( ) Z-scores subtracting the sample mean (y) from all values of y, and then dividing by the sample standard deviation (sy). z = (y-y)/sy. Sampling frame: the subset of the population from which a sample is to be drawn. Sampling variability: the variation of different random samples from one another. Each individual/combination of individuals has equal chance of being selected. Procedure: assign random number to each member of sampling frame and record data using the random numbers. Stratified: separate into different pre-defined groups (strata) perform srs on each group (e. g. student list stratified by faculty); mitigate against biases due to known differences between subgroups of the sampling frame. Cluster: splits population up into smaller groups (clusters) that are selected because they fairly represent entire population; each cluster contains no known differences from the entire population.
