In an experiment aimed at evaluating the effect of a memory-enhancing drug on the recall of a previously learned response. Either the drug or a placebo was administered to different groups of rats before the memory test. There were three trials of the memory test, and the dependent variable was the time it took the animal to make the correct response.
It seems reasonable that there is some sort of relationship between the number of trials it took to learn a response and the speed of response on the test trials. It would be interesting to know how the drug affects this relationship. How might you go about looking at this question?
A) Run a t test between the two groups' performance on the first test trial.
B) Correlate the number of learning trials with the speed of performance on the test trials.
C) Correlate number of learning trials and speed on test trials separately for the two drug conditions.
D) Use the Mann-Whitney test to compare the groups.

Question

Quizplus · Accepted Answer

Correlating the number of learning trials with the speed of performance on test trials for each of the drug conditions separately would allow for an investigation of how the drug affects the relationship between learning and performance. This approach would provide more information than simply comparing the two groups on the first trial (A) or using a non-parametric test like Mann-Whitney (D) which may not be as powerful. Correlating the two variables would also be more appropriate than running a t-test (A) as the dependent variable is not categorical.

In an Experiment Aimed at Evaluating the Effect of a Memory-Enhancing