Ch4Def - certain groups and subgroups are available Cluster...

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STAT 110 – Chapter 4 Definitions Population size does not affect confidence interval width significantly as long as the population is at least 100 times larger than the sample. sampling errors – errors caused by the act of taking a sample Æ They cause sample results to be different from the results of a census. random sampling error – results from chance selection in the simple random sample sampling frame – a list of individuals from which we will draw our sample Æ should list every individual in the population undercoverage – occurs when some groups in the population are left out of the process of choosing the sample nonsampling errors – errors not related to the act of selecting a sample from the population Æ can even be present in a census
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Multistage sample – used to select a sample, in stages, from a very large population where
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Unformatted text preview: certain groups and subgroups are available Cluster Sample - Divide population into clusters. Select one or more clusters and include everyone in those clusters in the sample. Systematic Sample - Take every n th item from the sampling frame . Stratified Random Sample Step 1 Divide the sampling frame into groups of individuals called strata. The strata are chosen using some characteristic of the individuals already known and of special interest. Examples race, gender, location Step 2 Take a separate SRS in each stratum and combine these to make up the stratified random sample. Probability Sample a sample chosen by chance A sample chosen in such a way that we know what samples are possible and what chance, or probability, each possible sample has to be chosen (not all need be equally probable)....
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Ch4Def - certain groups and subgroups are available Cluster...

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