That would explain a possible difference between an experimental group that spent a 15 minute exercise on stuff other than physics and a control group that did just physics- the best students might leave the experimental group, bringing down its mean and standard deviation. But as only the focus differed between the two groups, I don’t see how the impulse to leave classes that waste your time would manifest itself as a difference between the experimental and control groups. If such an effect is measurable in outcomes, it would not be noticed in this experiment.
Here I had just assumed one of the groups would have been taught some physics during that 15 minutes. I guess we’ll just have to keep wondering how much better teaching physics does at making people learn physics, than not teaching physics.
That would explain a possible difference between an experimental group that spent a 15 minute exercise on stuff other than physics and a control group that did just physics- the best students might leave the experimental group, bringing down its mean and standard deviation. But as only the focus differed between the two groups, I don’t see how the impulse to leave classes that waste your time would manifest itself as a difference between the experimental and control groups. If such an effect is measurable in outcomes, it would not be noticed in this experiment.
Ah, missed that detail, thanks.
Here I had just assumed one of the groups would have been taught some physics during that 15 minutes. I guess we’ll just have to keep wondering how much better teaching physics does at making people learn physics, than not teaching physics.