Math Blogs

Want an academic math job?

Tom Hull has a great piece on job interview advice for academic type math jobs. He wrote it over 10 years ago but recently revised it two months ago. You can find his interview advice on his webpage.

There is a lot of articles out there written to help people get jobs and survive interviews, but this article is specific for math majors wanting to go into academics. It includes questions you should expect at an interview, questions you should ask, what to do after the interview, and how to prepare for it.
He also has a bit of salary and negotiation, which is very helpful. He suggests:
“I do recommend that, in pretty much all situations, you ask for a
higher salary during job offer negotiations … My reasons for
suggesting this are two-fold: … Most
faculty do not get paid enough, partly because Deans and Provosts are
supposed to keep salaries as low as possible. Asking for higher
salaries upon being hired helps “fight the good fight” in terms of
letting administrators know that we should all be paid more. But the
main reason to ask for more money is that this could be the ONLY
chance you’ll have to significantly increase your salary for a good,
long time. Most schools have very rigid policies for salary raises
… and
thus you might not see another significant rise until you get tenure
or promotion.”

So if you are looking for an academic job in mathematics, I highly recommend checking out his site for some tips.

Should You Curve an Exam for Your Students?

There is a whole lot of math behind grading a paper, especially if you want to curve an exam. Dave Richeson talks about how to curve grades, so if you want to hear the math behind each of the 10 methods, follow the link at the bottom of this post.

When I give an exam to a class, I have an intuitive feeling for how the grade distribution should look. I know, roughly, who the A students are, who the F student’s are, and who the average students are. This comes from their homework, their questions in class, our conversations outside of class, and so forth. Individual students may surprise me and do better or worse than I expected, but as a whole, I know the strength of the class when exam-time rolls around. If the class does significantly lower than I think they should have, I will consider curving the exam.

Before you do any curving, you must determine what you want the curve to accomplish. Determining this will help you choose which curving technique to use. Here are some questions to ask yourself:
Do you want a particular average?
Do you want to give the lower-scoring students more of a curve or the same curve as the higher-scoring students? (Rarely do we want weaker students to get less of a curve than the stronger students.)
Do you want everyone to get a passing grade on the exam?
Is it OK to have a big group of A’s?
Is it OK for some students to have a grade over 100%?

Below I present ten techniques for curving an exam score.

1. Return, rewrite, regrade

2. Flat scale

3. High grade to 100%

4. Linear scale

5. Remove a question from the grading

6. Root functions

7. Bell curve

8. Extra credit problems

9. Grading by gravity

10. “I don’t believe in grades”/”I’m a grouch waiting for retirement” grading

If you want to hear what’s behind each of these 10 methods, click here.

 

What does a mathematician really do?

If you think some parts of math are hard to understand, you should try understanding a mathematician. Here is a quick preview of what goes on in the average day in the life of someone who chose this field of work.

Mostly, I sit at my desk for some time. I stare at a blank piece of paper. When I get tired of that, I might stare out of the window, or at the wall if in a basement office. After some time – maybe half an hour – I can’t stand it anymore. Now I have several choices: distract a friend and colleague from work and drag them to get some coffee; take a stroll to get the circulation going; or write something on that piece of paper. What I write on that paper will usually be only a slight variation of whatever I wrote on a different piece the day before – a piece now safely filed away in the “circular file”, or else buried somewhere in my office, or at home. The hope is that sooner or later this slight variation will lead me to an insight.

Then, some day, out of nowhere, I may have an idea. This could work! It’s a very good feeling, an idea. Can be an extraordinary high, in fact. Better not to think about it again for a day to preserve the good feeling (I know from experience that the idea is likely to be wrong, or useless). After a suitable time of enjoying the feeling of my idea, I’ll go back and check it out. Does it even make sense? Care is needed – questions may appear easier than they are (especially when under the influence – even a little alcohol makes everything seem clear).

Want to hear the rest of the story? Click here.

Coolest Teacher Explains Math

Kids are not always fond of math, but there are ways to make the process of falling in love with it easier. Meet Pierre the Mountain Climbing ant, a teacher’s tool for making the math class exciting and fun.

Increasing and Decreasing…

I just tell them that, for this, Pierre the Mountain Climbing ant always crawls from left to right – just like we read.

If Pierre is crawling uphill, the function is increasing. If Pierre is crawling downhill, the function is decreasing. (Ok, this is isn’t earth shattering… they get better! This is just the student’s first introduction to Pierre.)

The fun part is to draw Pierre on the graph… The trick is to make a really pathetic stick drawing ant:

Polynomials…

I always draw all the bodies first, then put all the arms in the air… Then I pause to admire my work and put the “Weeeee!” on. Delivery is everything. 😉

My students always remember what a polynomial is, since they can’t get this stupid picture out of their minds. I’ve seen their notes… They all draw the ants… and the “Weeee!”

I call these roller coaster graphs and draw Pierre and his friends taking a ride:

Limits…

This is where Pierre is most effective as a learning tool. By this time, the students are quite fond of him.

If you want to see the rest, check out the author’s website.

The problem with dating a mathematician

Should you date a mathematician? This is the question Tanya Khovanova asked herself on her blog. If you don’t know the answer from experience, you should look into what she has to say.

The book How to Drive Your Man Wild in Bed by Graham Masterton has a chapter on how to choose a lover. The list of bad features also includes professions to avoid. Can you guess the first profession on the list? OK, I think you should be able to meta-guess given the fact that I am writing about it. Indeed, the list on page 64 starts:

Avoid, on the whole, mathematicians…

I am an expert on NOT avoiding mathematicians: in fact, I’ve married three of them and dated x number of them. That isn’t necessarily because I like mathematicians so much; I just do not meet anyone else.

First, there are many mathematicians who, like my first husband, are very devoted to mathematics. I admire that devotion, but it means that they plan to do mathematics on Saturday nights and prefer to spend vacation at their desks. If they can only fit in one music concert per year, it is not enough for me. Of course, this applies to anyone who is obsessed by his work.

Second, there are mathematicians who believe that they are very smart. Smarter than many other people. They expand their credibility in math to other fields. They start going into biology, politics and relationships with the charisma of an expert, when in fact they do not have a clue what they are talking about.

For the conclusion, click here.

The Most Expensive Book on Amazon – $23 million

You might think that the most expensive book on Amazon has nothing to do with math, but in fact it has everything to do with it. Michael Eisen discovered that in a quest to set the price based on the competitor, two Amazon sellers managed to automatically and unknowingly set the price of a book to $23 million in just a few days.

At first I thought it was a joke – a graduate student with too much time on their hands. But there were TWO new copies for sale, each be offered for well over a million dollars. And the two sellers seemed not only legit, but fairly big time (over 8,000 and 125,000 ratings in the last year respectively). The prices looked random – suggesting they were set by a computer. But how did they get so out of whack?

Amazingly, when I reloaded the page the next day, both priced had gone UP! Each was now nearly $2.8 million. And whereas previously the prices were $400,000 apart, they were now within $5,000 of each other. Now I was intrigued, and I started to follow the page incessantly. By the end of the day the higher priced copy had gone up again. This time to $3,536,675.57. And now a pattern was emerging.

On the day we discovered the million dollar prices, the copy offered by bordeebook was1.270589 times the price of the copy offered by profnath. And now the bordeebook copy was 1.270589 times profnath again. So clearly at least one of the sellers was setting their price algorithmically in response to changes in the other’s price. I continued to watch carefully and the full pattern emerged.

Once a day profnath set their price to be 0.9983 times bordeebook’s price. The prices would remain close for several hours, until bordeebook “noticed” profnath’s change and elevated their price to 1.270589 times profnath’s higher price. The pattern continued perfectly for the next week.

If you want to read the whole story and the mathematical detective work behind it, go to michaeleisen.org

Why you should not pay for online dating

Christian Rudder over at the OkCupid Blog gives an in-depth analysis why the practice of paying for dates on sites like Match.com and eHarmony is fundamentally broken. It’s quite mathematical and he claims that 96.25% of profiles are ‘dead’. His subscriber flowchart sums it up pretty well:


online dating flow chart


Rudder says, “As you can see from the flow chart, the only way they don’t make money is to show subscribers to other subscribers. It’s the worst thing they can do for their business, because there’s no potential for new profit growth there.”