A lab researcher wants to find out whether mice will run through a maze quicker during the day or at night, after training. He has 100 mice available. He randomly assigns 50 of them into each group. He trains the first group to run the maze at 9:00 am and trains the second group to run the maze at 9:00 pm. Each mouse is trained the same way and the last three run times are recorded.

Part A: Describe what is being measured in this experiment and what variable is being manipulated.

Part B: Control, randomization, and replication are ways to design an experiment so that bias is reduced. Describe whether or not this experiment incorporates each of these principles into the experimental design.