Dear Dr. Mel, we are developing an evaluation program on the operation of the Action Committee Against Narcotics (ACAN). I am not sure about the sample size we need to conduct the survey. Could you please tell me if it is better to have a big sample size?

Thank you for asking.

Thanks for answering!

The sample size affects the power of a statistical test greatly. The larger the sample size, the smaller the variance of the sampling distribution of the mean. But you must remember that a larger sample size means a higher economic cost also. Hence, you may calculate the sample size based on your research funding.