Professor Yin was great. I've had some previous experience with probability, so many of the concepts are familiar, but this class uses a more formal approach with set theory. The professor spends a lot of time on examples, but they are well chosen to develop your ability to think about these kinds of problems. I didn't feel that any of them were repetitive, and they demonstrated important concepts from the course. Many came from very interesting questions as well. There are usually 5-8 questions per homework assignment, and these are usually more difficult or theoretical than the exam questions. The exams and grading are very fair.

Professor Yin is by far, the best professor I have had at UCLA. He is an extremely knowledgeable and clear lecturer. His lectures are extraordinarily engaging, both because he makes sure to explain the intuition behind concepts, to give proofs where he can, as well as to make jokes, share anecdotes, and make the class fun. His teaching style is simply fantastic. Sometimes he'll spend entire classes, or at least huge portions of classes, explaining just one concept, with big font on the chalkboard, to make sure we get it. I repeat - by far, the best professor I've had at UCLA. If you can take a class with him, TAKE IT.