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.

Question

Quizplus · Accepted Answer

The statement involves comparing the magnitude of improvement, which requires the dependent variable to be measured at the ratio level to ensure meaningful comparisons of differences and ratios.

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