Overall, 170A with Professor Tang is pretty meh

Good things:
1. Nice curve: He gives out 30-40% A/A-, which is nice
2. Low workload: We only had 2 graded homework assignments for the whole quarter. I barely spent time on this class except for a few days before the midterm and final
3. The midterms and finals were heavily based on class examples, homework and sample exams. I didn't need the textbook at all.

Bad things:
1. As the other reviews mention, he isn't a great lecturer. He goes really fast in lecture and often skips critical steps. If you ask him to re-explain things, however, he usually does.
2. Exams were pretty difficult, with midterm averages being ~60, and the final average being ~50.
3. He isn't very helpful: In office hours, I had to wait for long times as he would often be speaking to students in a non-English language. He also rescheduled his office hours once without telling us in class.

If you're really interested in learning the material, I'd recommend someone else. But, if you want a class with a low-ish workload and are willing to spend time at TA office hours, I'd recommend taking Tang

Best professor I have ever had. He is so helpful and his tests are pretty fair. He's very generous at curving are fair!

The absolute worst professor I've ever had. He refuses to pass back graded exams in class. If you want to see how well you did you have to go to office hours and pick the exam up in person. Then, he doesn't even show up to his own office hours. His lectures are also incredibly unclear! He is completely careless with his notation so if you don't already know what's going on, it can be really difficult to follow. The material itself is not that hard, but he goes over everything so quickly you don't get a chance to understand what's happening before he's already moved on. Also, he never bothers to move the blackboard up after he's done writing on it. If you're sitting in the back, you straight up don't get to see what he's writing. Homework and practice problems are poorly worded and confusing. He obviously doesn't proofread, because variable names and values will just change in the middle of the problem. If you're taking his class, going to discussion and TA office hours are a must (again, he doesn't show up to his own, so going to see him directly is not an option).

I literally made a bruinwalk profile just to set the record straight on this professor because he does NOT deserve a high rating. He is the least helpful, most ambiguous and downright the worst lecturer I’ve had at UCLA. It’s true, his tests are similar to the homework and yes it’s also true that the material for this class isn’t hard, or at least it wouldn’t be if you actually had a professor who could explain it. This class felt a lot like fumbling through a dark room, completely blind, trying to find a needle in a haystack, aka nearly impossible. Lectures were unclear and the textbook was equally unhelpful. The professor wouldn’t show up to office hours, but he was so arrogant in explaining things he probably wouldn’t have helped anyway. MANY times during lecture he would explain something with “because it is so” or “let’s move on because I think this makes sense” even if he entire class was staring blankly at the board. That being said, some people did do well in this class so maybe having a background in probability/statistics was assumed (I had none). Either way, you’ve been warned.

There are 3 parts in 170A: basics, discrete random variables, continuous random variables. Tang initially said there should be 5 to 7 homeworks. However, it turned out that he only assigned 3 homeworks altogether which correspond to the 3 topics.
Test is not hard except for the last question(which is optional if you have extra time). Questions are all from lecture notes, homework and practice exams, with a little change. I honestly don't get why most people scored badly in the exams because questions are all quite familiar. A one-page cheat sheet is allowed for each exam.
Overall, Tang is a great lecturer who teaches very clearly and is generous with giving As.