A research study is looking at two different methods of teaching mathematics. Student scores are measured after using those two methods. If students with strong reading skills do better with one method and those with low reading skills do better with the other method, then the level of reading skills (high or low) is functioning as a:

A research study is looking at two different methods of teaching mathematics. Student scores are measured after using those two methods. If students with strong reading skills do better with one method and those with low reading skills do better with the other method, then the level of reading skills (high or low) is functioning as a:

Moderator variable

Mediator variable