How do researchers decide on the size of a sample to use in quantitative research?

•   The decision about the best sample size depends on three things: 1) the degree of accuracy required, 2) how variable or diverse the population is, and 3) the number of variables being simultaneously examined during data analysis.
•   Larger samples are required if one requires a high degree of accuracy, if the population is very mixed or contains lots of different elements (e.g., lots of different ethnic groups in the case that ethnicity is a variable), and if the research is interested in examining many variables in the data analysis at the same time.
•   A smaller sample size is good enough when the population is similar (e.g., in age, religious affiliation, etc.), and when only a few variables are examined at the same time during data analysis.

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