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| − | The essential characteristic of probability sampling is a procedure where each person or item is given a known chance of inclusion and the procedure is used for the selection of individual items in the [[Population|Population]]. Possible methods are:
| + | Probability Sampling |
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| − | * Random sampling
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| − | ** Each individual has an equal chance of being selected.
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| − | ** Make sure more people are selected
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| − | * Stratification
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| − | ** If certain groups (or strata) can be identified before sample selection takes place it will be better to include this upfront. This is called stratification.
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| − | ** When you do not know the groups upfront you can identify those by asking a question:
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| − | *** "At the last general election which party did you vote for"
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| − | *** "Do you ride a motor cycle"
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| − | ** The retrospective use of information is known as post stratification.
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| − | * Cluster Sampling
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| − | ** If your population has a group or clusters which adequately represent the whole population it is more convenient and cost effective to select a random cluster and carry out a census for a complete cluster. This is called cluster sampling.
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| − | ** An interesting variant of cluster sampling is a ''random walk''. For instance, conduct interviews with every 5th house.
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| − | With ''multistage design'' a series of related samplings are conducted.
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| − | Part of: [[M7-Quantitative Decision Methods-S1 - Managing Data and Survey Methods|M7-Quantitative Decision Methods-S1 - Managing Data and Survey Methods]]
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| | [[Category:mbi]] | | [[Category:mbi]] |
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