A biologist hypothesizes that restricting food from mice will decrease their activity. He designs an experiment in which he observes the activity of 50 mice under restricted food regimens. Which of the following is true about his study?

A.
The study is well designed since it uses a large sample of mice.

B.
The study does not include a control group.

C.
The study includes too many variables.

D.
The results will allow the biologist to draw a valid conclusion.

I think it's A, can someone check? thanks :)

3 answers

I don't agree with your choice of A. What is the biologist comparing these 50 mice with? How will restricting the diet of 50 mice prove anything? Also, is 50 mice really a large number. That could be about 7% error.
No control. What is the biologist comparing the 50 mice to?
I agree with no control.