As of Fall 2019 this class is no longer reasonable. The class is clearly meant to weed students out of the statistics department and honestly, its working. The workload is entirely unreasonable (10- 15 hours per homework assignment, at times multiple homework assignments per week, 70% average on homework grades), tests are impossible (45 minutes for multiple choice and multiple coding free responses, 58% average on the first midterm), and professor Mike and TA Jake are extremely rude and unhelpful (condescending and will not answer questions). Do yourself a favor and do not take this class.

The workload is insane. Everyone took this course previous quarters told me this was an easy course, but not anymore. It really just takes all your study time. The exam is really ridiculous. People seem they might have no enough time to finish all the questions in 45 minutes. There are 15 multiple questions and two free responding questions that are subdivided by two, which are expected to be done in 45 minutes. Weekly homework is intensive as well. I really do not know why they make the homework unnecessarily hard even though they know most of the students in this course are mainly STEM majors who need to do other assignments too. Re-writing built-in functions in your own code is just time wasting and really useless. There are always time consuming and crazy problems that are time-consuming and depressing. One of the TA's named Jake unnecessarily yells at students when testing time is up, and the professor emphasizes mental well-being. HA! It is really all oxymoron. This course gives you depression for real. I don't know how he was previous quarters, but this is the worst course by far.

This class is trash. I've taken the PIC classes, I have programming experience and this class is extremely difficult and you are docked points for the most random and dumbest things. When you ask questions, the TA or the professor will respond in an extremely condescending tone so as to ensure that you know you're an idiot. The midterms are hard as fuck, and the homework is tedious and extremely difficult. Don't take it, the grade distribution is misleading as it was before they seemingly changed the rigor of this class...

fuck the stats department

General info:
The professor's lectures were pre-recorded and he mostly just read the content in the lecture notes. He has office hours during his normal lecture time.
We had 7 homework assignments (technically 8, but the last one was optional and mostly for final prep) throughout the quarter. Each homework is graded on satisfactory completion (so even if your answer is wrong, if the grader thinks you made a good enough effort, you'll still get full points).
We had a class Campuswire where the professor and TAs were fairly active on. You get extra credit for contributing to Campuswire discussions.
Our final project was cancelled, which was nice.
Tests are very difficult and almost everyone runs out of time. There is usually one question per test that is quite niche in the sense that you probably have never seen what is described in the problem unless you spend a lot of time experimenting around with R. If you want to do well on tests, learn how to debug code quickly, since that will take up a lot of time on tests if you aren't careful.
The raw scores for the midterms were pretty low, but the professor does scale them to increase your score a little.
Some stats for midterms (from the scaled scores, not the raw scores):
Midterm 1: median = 61, mean = 62
Midterm 2: median = 65, mean = 64
I had TA Jake and I interacted with him once in week 1 and then never saw him again. I think he stopped holding discussions after the first week, and I didn't see him post any discussion recordings on CCLE either. Maybe he did post recordings and I just didn't find them, I don't know. I did watch a couple discussion recordings from the other TAs though, they seemed pretty good and they gave some nice debugging examples.
This class is said to be an introductory programming class, but I would not recommend taking this class without any coding experience. There is so much material covered in so little time. If you are new to programming, be prepared to spend 10+ hours (outside of watching lecture videos) on this class per week if you want to get a good grade.
If you are new to coding, have a genuine interest in coding, and want to foster that genuine interest, do NOT take this class as your first programming class. Go take CS 31 instead... trust me.

My experience:
I came in with about 2 years of programming experience (took AP CS in high school, took CS 31, CS 32 at UCLA) and the tests in this class were still a time crunch. Homework assignments took me anywhere between 3 to 8 hours a week, depending on the assignment and how much effort I wanted to put in.
Towards the end of the quarter, I stopped watching lectures and just read the lecture notes, which I found more useful and time efficient.
If you are new to programming or would like to understand debugging more, I would recommend going to discussion. Otherwise, it's not really worth the time.

I can definitely say that Stats 20 is currently in a transition period as Mike is looking to intensify the rigor of the class to best prepare Stats majors for the 102 series. What this means is that you can expect to spend a good amount of time doing homework and an end-of-the-quarter project. You can also expect to see written response questions in the midterms that can usually get brutal in difficulty as well as multiple choice questions that requires extensive playing around on R to learn specific outputs.

Personally, I recommend that you take a programming class such as Python beforehand. I took C beforehand, and still managed to struggle. Then again, knowledge of C does not translate well into R (Python is somewhat more similar to R). There were also some students with no programming experience that were in better shape than I was, but they probably have better study habits than me (I don’t recommend taking multiple shots of vodka while studying). But yeah, anyways, Mike is a real kind dude and he would try his best to help out his students on Campuswire and in office hours with hints. He won’t outright tell you the answers to homework problems, as he expects you to learn by struggling, but it does give you a better sense of accomplishment when you get a difficult function to successfully run.

I’m going to be frank, I did get quite stressed with the class and I usually manage to get my stress under control during the most trying times. I’m sure a lot of other people got heavily stressed too. The other reviews weren’t joking that there were multiple homework assignments around the time of the second midterm and the final project did get delayed until a week and a half before finals week, so that is something you will have to get prepared for. Combined that with the fact that I had a difficult Linear Algebra class to deal with and let’s just say I got pretty awful scores for my midterms and final. However, you can ask Mike if you can take your midterm at another time (I forgot to do this, oops) as he knows the period during the midterms is just downright tough.

In the end, I got a B+, and I don’t even think I deserved that grade at all. Mike was once a student like us, and graded very leniently since he knows how being a college student is a real ordeal. At the same time, he put us through quite a wild ride in this class in the hopes that we become ready for the upper division Stats classes. Because of that, I now feel ready to take on anything upper division Stats classes toss at me, and I’m optimistic that my newfound skills in R will take me far. So don’t be afraid to take this class, just don’t expect an easy ride.

To anyone considering taking this class: understand that the course in its current state is flawed. Ideally, you shouldn't have to have prior programming experience to be able to succeed in this class, but as it stands, you should consider taking PIC 10A or CS 31 before attempting this class. Hopefully Stats 20 gets changed for the better in the future, but for now you'd be doing yourself a favor by getting some programming experience first.

Stats 20 has been redesigned to be much more rigorous. People struggled a lot this quarter.
The problem was with the way the class is designed. It tests you on your knowledge of R functions and nuances, when it should be testing your ABILITY to program in R. The exams were tricky and focused on details. They should've been testing statistical programming concepts, rather than testing if we memorized things that we could just Google in the real world. The Stats department needs to look to the CS department and follow their example in how to design an introductory programming course.

I appreciate the generous curve that Mike gave out in the end, and how gracefully he handled all the criticism he received over the course of the quarter. Mike really is a good professor and very supportive of his students. It's not his fault that this class was doomed. I only hope that he is just as vocal as we are to the Stats department about finding a solution for the issues in Stats 20.

Probably the worst class I've ever taken at UCLA. This is not an introductory level class workload. You cannot give your students a final project during week 10, and a final, and hw. Like ???? this is not the only class we're taking you need to CHILL OUT. Professor tries to tell us to be calm and no grade is worth you mental health blah blah oKAY THEN DON'T ASSIGN US WORK THAT'S GOING TO TAKE 45 HOURS TO COMPLETE. The material we learn in class is so far off from what we're assessed on in hw and on tests. I just have no words for this class but don't take it if you don't have to cause it straight up made me want to die.

Though I'm only a sophomore, but I'm 120% sure this is the most terrible learning experience in my entire academic career. There is 10 homework in total, all of which are graded extremely harshly (TA Jake has this incredibly strict grading rubric which he refuses to release to the class so you don't know what he expected for homework until the terrible grade is out with tons of comments for the smallest format details). A lot of the homework includes things he hasn't really cover in lectures. He just throws you a function and a brief description for that and expects you to figure out by the help section in r studio (the help section includes EVERYTHING in r, so basically he expects you to know everything because you can self-learn through that help section). He really likes giving out an unmanagable amount of homework and assignments before exams. Before the second midterm, we have three homework dues, one of them is to write 26 built-in functions. That homework takes me around 10 hours to write out functions that could work 99% percent of the situations. But what Jake expects are the most perfect functions that could work for even the most rare circumstances, and in PERFECT format, so I only get 53/100. By the way, he deducts points for using print() function which he thinks it's undesirable. So for one function even mine works perfectly, but I get 2 points deducted just because I use a function which he doesn't like. For thanksgiving holiday, we don't have class on Wed, but mike assigns a whole new chapter for us to self-study. Normally we spend about a week to learn a whole chapter, and mike just expects us to have enough time to self-learn a new chapter because we have one day off prior to thanksgiving. After thanksgiving is week 10, and we have another new chapter to learn, another homework for the new chapter due on week 10 Friday, and a Final Project that is SUPER HARD that takes me over 20 hours to work on which is due at the end of Final week. Mike constantly reminds us to have enough rest and enjoy our life and care about our mental health. This could not be more ironic because this class is the source of all my unhealthy schedule and heavy workload and mental health issues. Mike looks kind and he does act kindly and funny in class, but during his office hour he becomes super cold and intimidating. He never directly answers your questions but instead looking at you with a questioning eyes and ask what do you think. But the thing is if what I think is right, then I don't need to go to the office hour and ask! Jake is even worse. His office hour is a total waste of time. You have to sign up through a link and wait for an hour or so for him to call your name and get not really very useful feedback.
If you are truly in love with R language and are willing to spend every piece of your spare time to work on R , this class is perfect for you. As long as you have time and patience and passion, you can surely learn a lot. Otherwise, this will be the most horrible nightmare in your life.

Do you want to spend hours looking over your homework because even though you know it’s right, they will take points off for the most random stuff (like SPACING)?
Do you want to spend hours and hours on end studying, just for the midterm to be an assemble of questions that are so specific, you’ll have no idea how to answer unless you had the sheer luck of randomly encountering the same problem at some point in your life?
Do you like when your TA (Jake Kramer in particular) treats you like you are the worst idiot they have ever encountered in their life? Do you enjoy going to OH just so the TAs and the Professor can give you nothing but cryptic and confusing answers?
Do you love when it’s almost impossible (if you work at night and you can’t go to the Professor’s OH) for you to see your midterms, and to understand what you got wrong (which also makes your chances of getting a regrade, or checking if anything has been graded incorrectly absolutely impossible)?
If you are into all of these things, then you will LOVE this class.
Otherwise, if you have to take this class, mentally prepare to take one of the worst classes in your UCLA career.
I have an A in the class (at least so far), and I’ve never hated a class as much as I hate this one.
The professor tries to be nice, but most of the time he is unhelpful.
Jake Kramer is BY FAR the WORST TA I’ve ever had the misfortune to meet.
Anyway, GOOD LUCK! I hope you have a much better experience with the class than I personally did

This class might have been good in the past, but this is definitely no longer the case. I went for multiple office hours but it was one of those instances where he taught you 1+1=2 and then asked you to invent and think of a new color during the mid terms. Do not take this class at all cost - what everyone is saying here is actually true (apart from that one positive comment that is prolly written by Jake). Stay strong my fellow bruins, this class is GPA suicide and avoid it unless you have coded since a tender age of 3. PS: Jake is a spy from USC who's sole purpose is to destroy your GPA.