Which of the following is true with regard to variability and hypothesis testing?
A) As within-group variability increases, it becomes more likely that our experimental and control groups differ because our manipulation had a real effect.
B) As within-group variability increases, it becomes less likely that our experimental and control groups differ only by chance.
C) As within-group variability decreases, it becomes less likely that our experimental and control groups differ because our manipulation had a real effect.
D) As within-group variability increases, it becomes more likely that our experimental and control groups differ only by chance.
Answer: D