It is based on the responses logged by the 7sage community to that question. I don't think it's quite a perfect correlation, as I've seen questions with the same percentage of correct answers in adjacent difficulty "bands", but it's roughly based on that. ...
I think you may be talking about Section four and not section two. S4 has the psychic power question:
https://7sage.com/lsat_explanations/lsat-77-section-4-question-20
You can find JY doing LR in PT69 S1+S4, and PT71 S1+S3. And Jon also had an epic timed LR section video, which took him only 19 minutes. https://www.youtube.com/watch?v=F4vY0KpviJw&index=6&list=LLaknkMoRl59wmjfBX67-nFg