course
Probability Theory

Sep 2020

I took Probability Theory with David Rios. Unlike his intro stats class, I thought he was a damn good teacher for Probability Theory. His slides were clear and he explained the material thoroughly. His Office Hours were great. It's a hard class, but that's content not teaching. Overall, his teaching for the course was a little below-average for Columbia professors but that's normal. My personal suspicion is that he is totally plastered in the intro stats classes. I noticed they appear to be on his off days and he always came in a total wreck. In the intro stats course lectures, he swayed side to side a lot, really seemed out of it, said hilarious nonsense, and was unintelligible. Probability Theory was the opposite. Most lectures Rios was wearing a suit, was totally lucid and knew his stuff. I suspect he just doesn't care about the introductory classes.

May 2020

Professor Rios is a very chill professor. He is very approachable. But he did not take the class he taught as seriously as he should. He usually responds to 1 out of 5 emails you sent. He only will teach the very basic concepts during lectures (information you can get from watching youtube videos anyway). He would not bother working on hard problems with students in detail. To be honest, it is a misfortune that some Columbia students have to pay such high tuition and are required to spend their money on a class like this. In summary, I think Professor Rios is a nice person, but far from a good professor. (This statement stays true for a lot of the professors at Columbia.)

May 2017

Tests are really hard. Half the class already knows the material. If you're taking this as an intro to probability take it with someone else. She's not very good. Homework doesn't prepare for the finals. Poor explanation in lecture (her accent is fine, but her grammar is often in Chinese structure which results in really interesting phrases).