tobias.johnson@csi.cuny.edu
Office hours: Monday 12–1:30pm, Wednesday 9:30–10am in room 1S-225
I've posted your midterm scores on Brightspace. You can interpret your score as follows:
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 46 is a B+ and 47 is an A-, there is no big difference in getting a 46 rather than a 47 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 slides from today's class. See you on Wednesday for the midterm. Don't hesitate to email me if you have any questions as you review.
Our first midterm is on Wednesday, February 25th. Here are some old exams you can use to help you study. The best way to study for an exam is to practice exam-like problems in an exam-like setting. It's best not to look at the solutions until you're done solving (or trying to solve) all the problems on your own.
The exam will cover up to Section 6.4. You can use any calculator, but you can't use a phone or computer. You can also have a sheet of notes, which must be in your own handwriting on normal-sized 8.5 by 11 inch paper. You can write on both sides of the sheet. The exam will go from 10:10 to 11:50 with no breaks. In particular, I'd like everyone to remain in the room the entire time with no bathroom breaks.
Our schedule is a bit different for the next two weeks. There's no class on Monday for President's Day, and we won't have a quiz on Wednesday. The next homework isn't due until the following Monday, which is February 23rd. The next homework assignment after that won't be due until March 9th.
And then we have our first midterm on Wednesday, February 25th.Here are the solutions to yesterday's quiz.
I promised to link to some images showing a solid decomposed into discs and into shells. Actually, I found it a lot harder to find good images than I expected. I settled on these pictures (and also data files for 3-d printing) of a decomposition of a cone into discs and cylinders. They're simple but they get the point across.
Here are the solutions to today's quiz.