The Number of Subjects Needed for a Study _____

Multiple Choice

The number of subjects needed for a study _____.​

A) ​is determined by a mathematical formula and should be as small as possible
B) should be large enough to exclude differences between the control and experimental groups due to chance
C) should be kept small so that the data are manageable and there is less room for statistical error
D) is determined by a mathematical formula and should be large enough to exclude differences between the control and experimental groups due to chance
E) ​is determined by randomization and therefore,can be scaled as needed