Mariana Olvera-Cravioto

May 2015

This class started out very well - Prof. Olvera-Cravioto explained things very clearly, providing both intuitive and formal explanations. I think she probably went too slowly - do we need to spend more than 30 minutes reviewing how double integrals work? Then, there was a period of 2 weeks that she was gone at some conference, and two TAs filled in for her. The first TA was fine but the 2nd went way too fast and didn't explain things well. When Prof. Olvera-Cravioto came back, she picked up where they left off and was going as fast as she could to cover as much of the remaining content as possible. This ended up being very confusing - I don't think the class ever recovered.

May 2014

Mariana is an average teacher. She's super nice and you shouldn't be afraid to ask her for help. However, her teaching ability is questionable. She started off the class horribly slowly. It took us an entire 2 weeks to get to Bayes' Theorem. Don't worry though. She picks up the pace, in fact, her speed rises exponentially as the term progresses. Soon she's going so fast that you'll have no idea what on Earth is going on. As soon as we started joint distributions, most of the class got lost. She would show up, talk really fast and write down a bunch of equations and then have a quiz at the end. The textbook this class uses is garbage. You'll have to look up the textbook a lot to do the homework since she doesn't do enough examples in class. Try using Introduction to Probability and Statistics for Engineers and Scientists by Ross. It's infinitely better and Mariana actually teaches straight from it. Unfortunately, I only discovered this towards the end of the semester. The homework started off easy and got harder towards the end. It's still very doable, though you spend a lot of time going over your notes and textbook since you won't learn much from class. The quizzes are similar in difficulty to the homework. You might experience somewhat of a time crunch on many of them since she puts up the question on the projector and they're generally super long. You spend 3 minutes just reading the question. The final was OK. It had more probability than expected and very little statistics. Make sure you revise the older material so you don't get screwed during the final. Grading was fair to generous. Some weird stuff about her - Mariana likes talking about movies a lot and sometimes she says kind of racist things that are inappropriate for class. Nothing to worry about, but it's super funny when she goes off on these tangents. Overall, Mariana's an above average professor by Columbia standards. You'll learn a lot in this class. Probability is a super interesting topic, so if you're interested, you should definitely consider a class that goes into it in more depth than this one.

Dec 2010

On the first day, she started by saying that probability is hard and that it took her until after she received her PhD to truly understand it (which is really an indication of her lack of ability and of her condescending attitude. more on that later). She also told us that we shouldn't expect to understand probability in just a semester. That's a great way to start a class right? Lecture: She teaches right out of the book (which is available free on the internet as a pdf. So don't buy the textbook if you are fine with printing out the book). This means that if you are fine with reading from the textbook, then you will gain almost no extra understanding from attending class. Also, don't expect her to have a great handle on basic math concepts either. For example, she doesn't understand basic calculus. If you see the way she does double integrals, you will understand what I mean. Homework: She assigns a homework on Wednesday and it is due the following Wednesday. This means you will get plenty of practice. On the first day she promised us that she will write up all the problems in the homework and that we won't be able to find solutions. Don't worry. That is a lie. Most of her problems are copied verbatim from similar courses at other universities. So, with creative googling, you will probably find solutions to most problems. Exams: The exams are fair and open book/open notes. They usually take most students the whole class time. If you did the homework and know your way around the textbook and your notes, then you should be fine. Just a tip: print out the wikipedia pages for the different distributions like binomial, poisson, etc. the pages have some useful proofs and lists of useful expressions like PMF, MGF, etc. TL;DR: the class is manageable, and the professor is horrible. Find solutions to the HW on the web. Print out wiki and bring notes and book to exam. Lecture is straight out of textbook.

May 2010

If you got to be God for a day, I bet you couldn't create a being as rude, obnoxious and condescending as this professor. The TAs (John Zheng, Juan Li and Yiping Du) had the same attitude - "we are Ph.D.s, - undergrads are stupid and the cash cow MS students even stupider, so don't waste our time on doing the TA work for we are being paid because they don't deserve it." One gem includes telling us on Thursday, the last of the reading days, at 6:00 pm, that if you want your 2nd mid-term back you have only 1 chance to pick it up - tomorrow Friday 4-6 pm. The worst is how they took out the grade-book on course-works once the finals were done so that you never found out how much you got on the final. As far as I am concerned, this is what they did - due to graduations etc they had to submit grades by Friday night, 2 days after the exam - since the TAs grade those and Ph.D.s generally don't have exams this was doable, but why bother doing an all-nighter for these bunch of loser students so lets just put in the same score as their current average as the final exam score, assign the grade and not bother grading the finals, or do it eventually and make sure they get exactly what we put in earlier (given that grading in this course is completely arbitrary this is not very difficult to accomplish). I know that sounds impossible, but I don't put it beyond this teaching staff to do it. The shame is that this is probably the single most useful course to have taken when you end up on the job-market. So, do your best to avoid this professor and teaching staff.

May 2010

Mariana isn't really as nasty as the other reviews make her out to be. Though she does say some strange things in class eg smth like ' if you thought this class will be easy, you're wrong', from her grading system and course structure, it doesn't seem like she's really out to punish students. The exams are quite reasonable- if you work through the assignments (for which the TAs provide more than enough help for), it should be okay. Her lecture notes are also VERY structured and clear- perhaps even the best structured amongst the courses at the IEOR department I've done, which I really appreciated. I found that I didn't actually need to use the course textbook as all the required information was in the notes. Not sure about her lecture style as I didn't actually manage to make it to very many of the 9.10 am lectures. But from the few that I went to, and from comments by some friends, she seems like a pretty clear, well prepared lecturer.

May 2010

WORST PROFESSOR IVE EVER HAD BY FAR. Incredibly rude to students, condescending when asked questions, and basically just a cold heartless zombie. Simulation is a hard class to begin with, and hard classes come with questions - of which she will answer none because she feels you "should already know the answer". Stay away. for the fucking life of you - STAY AWAY. This can be impossible if you are ieor, as the department must have decided that Mariana is awesome enough that she should be the sole teacher of this class-- but if for some reason there is another option - take it. you'll hate yourself, and your life, and everything you once loved if Mariana is in your class schedule. trust me. The only plus side is she posts her lecture online, making it unnecessary to have to go to class and see the miracle that is a body working without a heart. P.S. she just had a baby, which is what a lot of students have been attributing her meanness to, but I had her for a different class, before the baby, and she was exactly the same way.

Oct 2009

Terrible, Terrible, and Terrible. she is extremely condescending - refuses to explain complex material in ways easier to understand. Told the class that she was "not afraid to fail many of us" if we didnt perform better. Horrible teacher for a class that shouldnt be that difficult. Avoid her at all costs.

Dec 2008

Very Hard class. make no mistake about it, this is a very hard class. It says its for people who have never seen probability, but its really not. If you haven't taken a class in probability before, don't take this class expecting to coast. Mariana is a good professor who follows lectures very closely to the textbook. The course starts off easy, but gets very hard in the middle section. By the end, this was a big time commitment with homework, which would have been impossible without the recitation where the TA gave you the answers(go to recitation!) Overall, tough tough class with a good professor.

Apr 2007

Professor Cravioto is straightforward. Her lectures follow very closely to the text about 70% of the time. The thing is, her lectures are very concise and she tells you all the information you need to know. The homework assignments arent too taxing but there is usually a problem or two that will take some thought, especially if like me you had no exposure to probability/statistics before. I recommend attending recitations because TAs clarify somethings you may not get from her lectures. The first midterm was insanely easy, the second (almost in response) was way harder with a fair number of people failing it, and the final was fair and not too hard at all.

Feb 2007

Possibly the worst class I have ever taken at Columbia. She was new this year and seemed not to realize that the problems sets should not be exceedingly difficult for an introductory probability course. The exams were straightforward.

Jan 2007

Prof. Olvera was great. I thought Simulation was going to be a nightmare but Mariana made it much bearable. Class starts off relatively easy but gets pretty complicated after a while. You should attend most of the classes and at least a few of the recitations if you want to do well. A background in programming helps a little but more importantly you need to have a solid understanding of probability as she spends little time reviewing. Everything before the midterm is a lot easier than everything afterwards so study hard for the midterm and get an average score. After that you should be fine for the course as long as you do all your home works and do a good job on your project. The final is a bit tricky but if you managed to attend most of the classes or review the lecture notes weekly and remain on top of the material you should be fine. Luckily she posts her notes online so you always have notes handy even if you never went to class.