Sample Size Calculation

Written by Scott Martin
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The goal of sample size calculation is to determine the ideal, or minimum, sample size. Through this statistical process, you can ensure that you are trying to get a sufficient number of participants of observation so you can generate statistically valid results from your project. Furthermore, you can prevent yourself from needlessly wasting resources on an accidental over-sampling.

Purpose of a Sample Size Calculation

Another purpose of conducting sample size calculations is to reduce the sampling error. It is not possible to determine the exact size of this error, but it is assured that it will occur with each sample. This is the error that exists in every study, since a study is carried out with a sample and not with the entire population.

One way to reduce sampling error is to increase the sample size. In order to figure out the size of the sample at which the sampling error is acceptable, you can use sample size calculation. This way, you will not conduct a study with 1,000 participant when you in actuality only needed 300 to create a robust sample. Again, this calculation will also give you an idea of the minimum number of participants required.

Many statistical software packages can perform sample size calculations. However, the calculation can depend on your research design and anticipated analytical techniques. It is useful to work with a statistician in order to use the correct calculation and variables.


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