Math 311

Today's quiz will be delayed until Wednesday, because Webwork has been down since at least sometime yesterday. I don't think it's fair to make you take the quiz when you can't look back at the old homework questions and their solutions.

Office hours this morning are delayed till approximately 11:05am this morning because I have to do a course observation in our department. This is the last one of the semester so after this office hours should be normal again. Alaso sorry for the repeated announcements on Brightspace and here, I just wanted to make sure everyone got the message.

I've changed the dates for the next homework assignment and quiz. Originally I had the next homework due on Wednesday, October 22nd, and the next quiz on Friday, October 24th (when CSI has a Monday schedule). Because of the unusual days, I've decided to push both back a class. So the homework will be due on Friday, October 24th, and the quiz will be on Monday, October 27th.

I've posted your midterm scores on Brightspace. You can interpret your score as follows:

• 38–47: A- to A
• 28–37: B- to B+
• 20–27: C to C+

Anything lower than that is a D or an F.

In the interest of transparency, and also because I hate answering questions about I assign grades, let me explain in as much detail as possible how I assign grades for the class. For each midterm and final, after I grade the test, I make a gradescale as above. I don't set the scale to make a certain number of A's, B's, and C's. Rather, I look at the tests and try to judge what scores match my expectations for what merits an A, B, or C. This means that if everyone in the class does well, I set the gradescale so that there are more A's.

When it comes time to assign final grades for the course, I use the gradescales to convert the midterm and final scores to a numerical scale of 0–100. In more detail, I convert the low end of the A range to 90, the low end of the B range to 80, etc. I set the high end of the A range to something above 100. For scores in the middle of a range, I interpolate linearly to convert them to the numerical scale. As a consequence, even though the gradescale for this exam says that 37 is a B+ and 38 is an A-, there is no big difference in getting a 37 rather than a 38 on this exam. When converted to the numerical scale, you'd just be getting an 89 instead of a 90 or something like that.

For the homework and quiz part of the grade, I also convert your scores to the numerical grade, though I'm a bit more ad hoc about it. Finally, I take all your numerical grades and compute a weighted average according to the weights given in the syllabus and arrive at your final numerical grades. Then, I make the final letter grades based on these. Roughly speaking, I'd convert numerical grades of 90 and above to an A or A-, grades of 80 to 90 to a B+, B, or B-, etc., but I use my judgment when setting the cutoffs (it's not like I'm giving people who got a numerical grade of 89.9 a B+).

One very special grading policy that I have: If you ask me whether I grade on a curve, I will ask you questions about what you mean by grading on a curve, probably until you give up asking your question. (If you can explain to me what you mean by grading on a curve, I am happy to answer the question, but it is not very common that anyone has a clear sense of what it means to grade on a curve.) I do hope that my explanation here is enough that you'll understand how the grading works.

Here are the solutions to yesterday's exam.

Our first exam will be on Wednesday, October 8th.

• The midterm will cover all sections of the textbook up to and including 2.3 (sections 1.1, 1.2, 1.3, 1.4, 1.5, 2.1, 2.2, and 2.3).
• No calculators, cell phones, or other electronic devices are allowed. But as usual you can leave your answers unsimplified.
• You may bring with you a two-sided, one-sheet set of notes (on normal-sized paper) in your own handwriting.

Here are some old exams that you can use to prepare. There are solutions posted as well. Note that there's some variation in exam timing, so some of the exams contain questions on topics we haven't reached yet.

The best way to study is to take practice exams under exam-like conditions. The solutions are useful to check your answer after you've solved it, but it won't help you much if you just study by reading the solutions. Even if you've completely stuck on a problem, you'll do better if you email me for a hint rather than look at the solution.

Since the course schedule has been so weird, I'm holding open the homework assignment due today for an additional day. So you now have until tomorrow, Tuesday, September 30th, at 11:59pm, to finish this assignment.

Here are the solutions to today's quiz.

Here are the solutions to today's quiz.

Just a reminder that we're having a short quiz at the end of class tomorrow. As usual, the problems will be very similar to the homework that was due yesterday. Note that there's now a solution posted there to Problem 6. I don't post full solutions to every problem, but I try to write solutions for the harder ones. If there's ever a problem that you'd like to see a solution for, please let me know and I can write one.

Welcome to Math 311, Probability. We meet in room 3S-107 from 2:30 to 4:10 on Mondays and Wednesdays. The first class is on Wednesday, August 27th. The textbook for the class is Introduction to Probability by Anderson, Seppäläinen, and Valkó. We'll follow the textbook very closely, and you will want a copy (it's usually a lot easier to look back at things in a textbook than in your own notes). A used version of the textbook is just as good as new. The book is also on reserve at the library.

You can find some important information on the class in the syllabus. A more detailed schedule for the class is given in this calendar. The class will include online homework through WebWork (see Homework). The first assignment will be due September 8th.

I'll see you all in class today and am looking forward to a good semester!