Professor Middlebrain notes that rats in the first 10 cages, which were injected with salt water, are calm. Rats in the last 10 cages, which were injected with distilled water, are aggressive. He concludes that salt decreases aggressiveness. What is wrong with this study?

Question

Quizplus · Accepted Answer

The study lacks random assignment, which means that there is no control over individual differences in the two groups. It is possible that there were pre-existing differences between the rats that were assigned to the different conditions, which could explain the observed results. Additionally, there may be other confounding variables that were not controlled for, such as differences in the rat's age or gender. Therefore, it is not possible to draw a valid conclusion about the effect of salt on aggressiveness based on this study alone.

Professor Middlebrain Notes That Rats in the First 10 Cages