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Unformatted text preview: makes listing or counting counting every element impossible. • The random number selection procedure cannot be used for infinite populations.
Slide 22 Other Sampling Methods
Covered Covered Simple Random Sampling Other Other Types • Stratified Random Sampling • Cluster Sampling • Systematic Sampling • Convenience Sampling • Judgment Sampling Slide 23 Stratified Random Sampling
The The population is first divided into groups of elements called strata (subsets of population). (subsets • Best results are obtained when the elements within each stratum are as much alike as possible (i.e. are homogeneous groups). A simple random sample is taken from each stratum. sim Formulas Formulas are available for combining the stratum sample results into one population parameter estimate. Slide 24 8 Stratified Random Sampling
Advantage Advantage: If strata are homogeneous, • as precise as simple random sampling • but with a smaller total sample size. Example Example: The basis for forming the strata might be department, location, age, industry type, etc. Slide 25 Cluster Sampling
The The population is first divided int...
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- Spring '08