Which of the following is a threat to internal validity in a randomized control trial?
A. Crossovers
B. Random sampling
C. Both A and B
D. Neither A nor B
Answer: A. Crossovers
Which of the following is a threat to internal validity in a randomized control trial?
A. Crossovers
B. Random sampling
C. Both A and B
D. Neither A nor B
Answer: A. Crossovers