In Describing Research Results, Statements Such as "The Mean Experimental

Multiple Choice

In describing research results, statements such as "The mean experimental group score improved twice as much as the mean control group score" should be made only when the

A) dependent variable is measured at the ratio level.
B) study that produced the results was a true experiment.
C) research participants constitute a representative sample of the population.
D) study meets all of the above criteria.