## Sunday, May 25, 2008

### Danger: steep grades

No traction

This semester I managed to be simultaneously cruel and clueless. You could ask my students. Well, some of them anyway.

Most of the math students who took the opportunity to review our classes had nice things to say. (“This class is the best.” “Your [sic] doing a great job.” “Dr. Z is the best teacher ever!” “Math isn't as difficult as I thought it was.” “I learned that learning can be fun.”) That's gratifying, of course, but no teacher is going to please all of the students all of the time. Spring semester provided solid evidence to that effect.

How dare you!

Perhaps it's different in other courses, but math classes always contain a few paranoid students who think you are out to get them. I sinned by both omission and commission in my prealgebra class. Although I adopted a custom-published text that was pared down to the chapters we really needed, it still contained a few sections that we skipped. Anxious students inquired multiple times whether it was really okay to ignore those pages. “Won't we need this later?” If you do, it'll be covered then. It's not part of our course syllabus. Most of them calmed down. (Most of them. Not all.)

My sin of commission was far worse. I decided to add a unit on weighted averages. Lots of teachers give grades based on weighted averages, but lots of students have no idea what that means. I was going to help my students understand their grades. They were understandably horrified because it was not in our textbook. Was a teacher allowed to do such a thing? My students seriously doubted it. I forged ahead anyway.

“All of you know about regular averages, right? When you just take two numbers, add them together, and divide by two?”

All the heads nodded. They knew. Or were willing to pretend that they did.

We had just done the unit on percentages. I showed them that adding 50% of one number to 50% of a second number produced a result equal to the customary average. Then I tweaked it. How about 30% of one number plus 70% of a second number? The result will be closer to the second number because of its greater weight, right?

More nodding.

Some of them got it. We did several problems. As long as the weights added up to 100%, we could choose whatever weights we wanted. We could even distribute the weight over more than two numbers. I was delighted with the responses. A couple of students expressed relief that they now understood how their grades were computed.

Some of the students were just humoring me, of course, as I discovered on subsequent quizzes. And the students who attended only occasionally were left entirely in the dark, but didn't even know they had missed something extra. That ensured that they didn't complain—at least not until they showed up for the next exam and were taken entirely by surprise.

Then they complained. My sympathy was not overwhelming.

Not the grade I wanted

I can always expect a few urgent e-mail messages after semester grades are posted. These seldom have any relation to reality:
i have received the grades and i found out that i got D in the class. please i dont want to retake the class again help me out to get C
You know, with a weighted average of 61.0% for your course grade, I don't think that's going to translate into a C.

Of course, I could have told him that sooner. In fact, I had told him that before. Before the final exam I posted target scores for the final exam. This student had been failing exams all semester. The posted target score for him was 144% on the final exam if he wanted to get a C in the class. That was certainly not going to happen. I thought he showed up for the final exam just for the experience. No. He thought he still had a shot at a passing grade. (That shows how poorly I taught him.)

Another student was a master of understatement:
I was wondering did I really do that bad on the final and in the class, overall?

I can see where I slipped up a few times.
A “few” times? She had missed more than half of the in-class assignments. She simply hadn't been there. My student had apparently decided that showing up on exam days would suffice. Close, but no cigar. No passing grade, either. Especially not with a score of 54% on the final exam.

I wrote her back: “If you had skipped class less often and taken more of the quizzes, your in-class score would not have been so low. That 33% score on in-class work did not help you at all.”

Hey, I'm a master of understatement, too.
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