a moderator variable is (penyederhana) one that influences the strength of a relationship between two other variables, and a mediator variable (penengah/pengantara) is one that explains the relationship between the two other variables. Mediation analysis facilitates a better understanding of the relationship between the independent and dependent variables when the variables appear to not have a definite connection

As an example, let’s consider the relationship between social class (SES) and frequency of breast self-exams (BSE).

Age might be a moderator variable, in that the relation between SES and BSE could be stronger for older women and less strong or nonexistent for younger women.

Education might be a mediator variable in that it explains why there is a relation between SES and BSE. When you remove the effect of education, the relation between SES and BSE might disappear.