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Sampling (Types of Sampling (Convenience sampling (Uses those who are…
Sampling
Types of Sampling
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Cluster sampling
A random sample of clusters is taken, then all units within the cluster are examined.
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Systematic sampling
After randomly selecting a starting point from the population between 1 and *n, every nth unit is selected.
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Defining the Population
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Often, the units in the population can be identified by existing information such as pay-rolls, company lists, government registers etc.
A sampling frame could also be geographical. For example, postcodes have become a well-used means of selecting a sample.
Sample Size
key factors
2.To lower the margin of error usually requires a larger sample size: the amount of variability in the population, ie the range of values or opinions, will also affect accuracy and therefore size of the sample
3.The confidence level is the likelihood that the results obtained from the sample lie within a required precision.
1.No estimate taken from a sample is expected to be exact: assumptions about the overall population based on the results of a sample will have an attached margin of error
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In market research, sampling means getting opinions from a number of people, chosen from a specific group, in order to find out about the whole group.