Sample size determination is an important step in conducting research since it should provide the necessary information about the population of the study. In case the sample size is smaller than expected, the obtained results of the study cannot be generalized to the target population. On the other hand, the larger the sample size the more precise the findings. However, it is not usually possible to have a large sample size due to research limitations, such as cost, time, or the convenience of collecting the data. There are different approaches to calculating the sample size:

Regardless of the employed method of sample size determination, it is worth considering the following points:

Sample size determination depends on the type of the main variables of the study whether qualitative or quantitative. In fact, a smaller size of the sample is required when the variables are qualitative.

A smaller sample size is required in interventional studies when the intervention is strong enough. When the study is descriptive commonly the larger groups are expected to reach the best results.

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