In a Neurological Study of the Effect of Environment on Mental

Multiple Choice

In a neurological study of the effect of environment on mental development, rats were randomly assigned to be raised in one of the four following test conditions: Impoverished (wire mesh cage - housed alone) , Standard (cage with other rats) , Enriched (cage with other rats and toys) , and Super Enriched (cage with other rats and toys changed on a periodic basis) . After two months, the rats were tested on a variety of learning measures, one of them being the number of attempts needed to learn to navigate a maze. The data for the maze task are below, along with means and standard deviation for each group.
-What are the observational units?

A) Months
B) Toys
C) Test conditions
D) Rats