This class is fairly hard, as expected. But as far as hard, mathy, stats classes go, I honestly liked this one. Amini recorded everything and posted the lecture slides he writes on in class, so you don't have to go to class at all. The lecture slides are honestly amazing (when they include his writing after lecture). The slides were enough for me to gain the understanding I needed. The exams are doable, much more so than Christou's (and you get a day or more to do them). I have no doubt many people if not most of the class was cheating/working together on them because there was nothing stopping you. The one thing I would say is that he ended up keeping track of who went to class and boosting the grades of people who went to class a lot, even tho attendance wasn't mandatory. That's kind of dumb in my opinion.

One of the WORST professor of this department. He always asked us to watch previously recorded lectures before we go to the class, but after doing this I found it useless to go to lectures or watch current recorded lectures. The reason is that the content of previous videos is basically the same as that of current videos. Amini cannot explain concepts well, and his lectures are lack of concrete examples; instead, there are tons of dry theorems and lemmas. Sometimes he skipped some concepts or spent little on time them, and those content turned out to be tested on exams. When it comes to exams, both midterm and final are very hard, often relating to untaught or unemphasized concepts. The overall feeling of the class is so bad that i would never take his class again.

I really enjoyed taking 100C with professor Amini, I took this class along with 101A, and I can safely say that I gained all my understanding from 100C with Amini.
It is a theory heavy course, which I really appreciated, because this course really provides some absolutely essential understanding for statistics.

There was a lot of homework, but I learned a lot from doing them.
Tests were hard, but appropriately, although a bit more time would have been nice for the final, I ended up rushing through the last questions.

Prof Amini prefers having people participate in the lectures, and turn it more into a sort of discussion session, which was rather refreshing.
If you are not afraid to put yourself out there, and participate in class, this is a really good class for you.

Anyways, hard, I learned a ton, 10/10 would take it again.