Question

A researcher plans a study whereby she will compute three statistical tests: a Pearson r, a paired samples t-test, and multiple regression. She performs a power analysis based on an anticipated R²and enrolls the required number of participants based on the results of that power analysis, states that the study has adequate statistical power, and begins the study. Is the researcher correct? Provide a rationale for your answer.

Answer 1

Power analysis is normally conducted before data collection. The main purpose underlying power analysis is to help researcher to determine the smallest sample size that is suitable to detect the effect of a given test at the desired level of significance. The reason for applying power analysis is ideally, the investigator desires a smaller sample because larger samples are often costlier than smaller samples.

power analysis generates certain guidelines for the size of the sample but cannot reflect the complexities that a researcher comes across while doing certain research projects, but yes the researcher is doing it in a correct way by using power analysis after doing above tests.