The answer is "Eating chocolate causes students’ test scores to increase".
An experiment regarding experiment to bunches enables us to decide cause and effect.
Random assignment of members guarantees that any contrasts between and inside the gatherings are not efficient at the start of the test.
While there are distinctive approaches to take a gander at connections amongst variables, and examination is the most ideal approach to get a reasonable thought if there is a cause-and-effect connection between at least two variables.