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.
Everybody wasted 15 minutes. The question was just what they focused on (and both options weren’t physics related).
I think I might be missing your point—I already thought that was the case.
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.