STAY AWAY from Christou. His exams are psychological experiments, and do not measure what you know. The midterms are not inherently difficult, but there is not nearly enough time to complete them.

His final exam? A total joke. It doesn't matter how much you study you will not do well. And he tells us this! "The test will be hard and long." I don't need to hear that when I have three other finals to worry about. I ended up with a grade that I did not deserve even after all of my hard work.

Then he tells us "grades will be submitted on Tuesday" and they don't appear until a week later.

I am NOT taking Christou for 100B solely because of his ridiculous final exam.

This course makes me feel like a complete RETARD. I have no complaint at all regarding Professor Christou, as he is a really helpful professor. I could say that he has tried his best to deliver the course materials, but they are still so hard for me. The average for exam1 is around 27/100, and the final is even harder than exam 1. When doing the tests, you will find that your efforts paid in reviewing past exams and hws are meaningless, as there are very few similar questions.

If you're not a natural at math or don't have strong mental health, don't take this class. For pretty much every homework question on every assignment, I used the TA's notes (who thankfully went over every question). Christou does hold many many office hours, but when asked a question about a certain problem, and he explains quickly and not in depth at all. Like previous reviews, the exams are absolutely terrible and made me cry. Despite the grade I got, I felt that I did not learn anything from this class.

Professor Christou is one of the most caring and dedicated professors I have ever had; he hosts 2-hour office hours six days a week. That being said, this was the most stressful class I have taken during my time at UCLA, and proved to be extremely difficult for almost everyone in the class (apparently harder than most math/engineering/CS upper divs). Many will choose to take Christou again because of his generous curve, but if you do end up having a class with him, just make sure you take your grades and your workload with a grain of salt so you don't end up exerting yourself too much mentally.

Grade breakdown:
Midterms x2, 25% each
• These midterms were ridiculously difficult; I studied the same amount for both, ended up with a 43% on the first one and 26% on the second, and felt like whatever score I got was just a matter of luck. Midterms were open-note but averages were still 28% for both, and if you scored above a 30% you were in the A range.
Homework 15%
• There were NINETEEN homework assignments in ten weeks, with an average of 4 questions per assignment. They take up so much time and are ridiculously hard as well; personally don't feel like Christou was very helpful during office hours since he would often tell me to look at the answer key, but maybe I was just asking the wrong questions. Initially homework was stressful because they graded on accuracy, but they switched to grading on completion mid-quarter after realizing that it was impossible for people not to fail their assignments. Hopefully they keep it that way for future quarters.
Final 35%
• Similar to midterm, just felt like 3 hours of suffering to me. One person tried to leave early and give up on the final, but Christou looked through his paper and asked him kindly to sit down and try to complete it. You could tell it was because he cared for the student and wanted to him to succeed. By the end of it, I was so glad the class was over.

TL;DR: Overall, this class was really emotionally difficult for me and was extremely challenging. Christou really is a kind soul and is well-loved by his past students, and I can see why – he cares for his students and always told us to study well because it would be helpful for our future. But if you choose to take this class with him, be prepared for an intense workload and horrible raw scores, though you can always trust the curve.

Pros: Heavy scaling on exams, around 30% was an A for the midterms. Many office hours. Had a great TA, Conor, (definitely recommend going to his discussions).

Cons: Lots of homework, 2-3 a week, ended with 19 homework assignments total. Christou goes through the material very quickly in lecture and jumps around in his handouts a lot. Sometimes, a lecture might not even have a handout, overall, kind of disorganized, so come in expecting that. Exams are nigh impossible to complete, not good for mental health.

Tips: The exams are open notes, and many similar question types are covered in lecture and homeworks. Therefore, some questions, you might just end up copying the process from your notes. Understanding how concepts are related and being able to identify problem types are a very useful skill in the exam (again, since open notes, being able to identify the problem might be 90% of the work). Also, the Penn State stats 414/415 notes recommended below explained concepts pretty nicely.

Overall, this is a demoralizing class with a lot of content, but Christou's heavy scaling makes it fine in the end, so just keep in mind you'll probably do ok :)

My favorite class with my favorite class at UCLA. Very applicable material to real life situations and super helpful knowledge to spill upon during interviews. The tests are difficult but not impossible and Professor Christou always curves VERY generously. Like the other person said, the workload is a bit heavy at times (1 hw due/week and sometimes a project update (coded in R) due) but its not unbearable and Professor Christou has always helped me through problems I don't understand during OH (which is has every single day and on weekends before exams - amazing). He doesn't really care about deadlines but rather puts a focus on students well being and understanding of the material. I appreciate this a lot.

I like professor Christou despite his tough tests. I believe passion is the most valuable quality of a good lecturer, and you can definitely see it in professor Christou. He holds office hours nearly every day, and he is always willing to respond to emails and gives detailed explanations about concepts.

Yes, you can't get an easy A in this class, and yes, you have to spend many hours in this course to master the material truly. But taking 100C with him will help you more than if you take it with a professor that gives everyone an A. Believe me. I regret taking 100A with a very nice professor who gives everyone an A because I later found out I don't master the content in probability theory and encountered many obstacles in other courses that build upon it.

Christou is the most unorganized professor I've ever had. He doesn't teach in a linear path and countlessly flips back and forth between his handouts during lectures. He can't teach one topic without referencing 3 previous topics and takes too much time clarifying concepts no one was confused about. I stopped going to lecture because I didn't learn much; I just did his handouts at home and used online resources (look up PSU's online mathematical statistics class, Stat 414). The curve was indicative of how poorly this class was taught, with a 53% being an A. Print the solutions to old exams and bring them to the midterm since he reuses questions.

This class made me question my career path and literally contemplate suicide because of how difficult it was. I was only relieved after I got my grade back because of how generous his curve was but before that, the class was torture because I didn't know if I was going to fail. Like other reviewers have said, his exams and homework are extremely difficult and grades around 30% or lower are not uncommon, and the class takes a toll on your mental health.

Christou is genuinely a caring person and is willing to devote time to office hours seven days a week. He's willing to listen to students and I like him as a person, more than any other faculty member I've studied under at UCLA. However, I cannot recommend him as a lecturer.

His lectures often jump straight into mathematical proof without attempting to establish some purpose or a conceptual basis for the equations that he's writing down. His homework follows the same pattern, often consisting of manipulating one equation into another equation without some sort of conceptual motivation behind it. Even when the solutions to the homework are released, the process of going from Start -> End is often just substituting different equations into one another until you arrive at the goal. It's very easy to get lost in the math, especially when he frequently jumps around, skips steps, is generally inconsistent with his delivery of notes and class materials, and talks extremely fast.

The fact that he does not follow a textbook also exacerbates this problem. He uploads his notes, but they are often an equation-only outline of the concepts meant to be learned. Without a textbook, there is no comprehensive material to fall back on to further study the material. Pre-written notes with explanations (not just equations) would be extremely helpful.

Many reviews have said that his classes will teach you more, but I disagree. The rigor of a class isn't the same as its effectiveness. When the class gets an average of 30% on exams can you really say that the students learned a significant amount of material, or did they just manage to get 30% of the partial credit by regurgitating equations? I've gotten lower grades in classes where I felt like I learned more than this class in which I got a B-.

This class, taught in fall 2021, requires students to use R to analyze several datasets containing the price of major stocks. Don't worry if you have never used R before; instructions are given before the beginning of the class, and you just run through his given commands on R. Professor Christou is clearly passionate about teaching and wants to spread the knowledge to the class. He's a very approachable if you have any question regarding either the course material or guidance. Overall, I recommend this course to you if you are interested in analyzing the stock market data with R in future, or if you are interested in getting guidance from a very knowledgeable professor.