Crazy Math Coordinator

[Balain]

So after our first linear algebra exam our prof told us because our class average was 70% our marks were far too high so the math coordinator has decided t make the next exam much harder.

Well I thought I did pretty good on it. when I wrote it.

Well today our prof started the lecture with "I have most of the exams marked and it isn't good. One person even beat the odds and got 0% on the multiple choice section. The grades were abysmal.

Man I hope I did well, but what the heck making the exam way harder because the class average was 70% GAH

[Sgt. Cookie]

Sounds like the guy went too far in the other direction. Have a chat with him about it.

[nedz]

Think of it as a test of his teaching ability :smallamused:

[Zahhak]

linear algebra

Are you a math major? o.O

[u-gotNOgame]

Are you a math major? o.O

At my school everyone in the engineering school is required calc 3 and 4 (linear algebra/differential equations and multivariable calc).

40-50% averages are pretty common as you move up the ladder in the sciences, you just have to get used to trying to beat averages not do objectively well. Most of the tests I've taken past 100 level courses are written to be to long to finish. You pick and choose what you can do well and then leave the rest. Most of the time I only get answers down for about 60-70% of the points on the tests.

The good news is if everyone did universally horrible on this exam it'll hurt the mean course grade so you'll just need less points to get the same marks than if all the test averages were 70%. All in all, I'd take a 40% average test over a 70% average any day. There's more room to beat the deviation on the high side and to me it's less stressful knowing I only have to finish 2 of the 4 questions.

-UGNG

tl;dr: keep calm and carry on

[snoopy13a]

In my undergrad, a mean of 50% for science exams was common.

If you are only competing against your section, then harder exams can be better. They allow better students more opportunities to separate themselves from the average and below-average students. An easy exam bunches more students at the mean so that a silly mistake can doom one to a low score.

Your actual score means little. What is important is your score compared to the mean and the standard deviation.

[Zahhak]

At my school everyone in the engineering school is required calc 3 and 4 (linear algebra/differential equations and multivariable calc).

Ah. At my school we have up to Calc 3, a differential equations course that usually comes right after, and Linear Algebra is its own thing, and I think its a senior level course.

[noparlpf]

At my school everyone in the engineering school is required calc 3 and 4 (linear algebra/differential equations and multivariable calc).

40-50% averages are pretty common as you move up the ladder in the sciences, you just have to get used to trying to beat averages not do objectively well. Most of the tests I've taken past 100 level courses are written to be to long to finish. You pick and choose what you can do well and then leave the rest. Most of the time I only get answers down for about 60-70% of the points on the tests.

The good news is if everyone did universally horrible on this exam it'll hurt the mean course grade so you'll just need less points to get the same marks than if all the test averages were 70%. All in all, I'd take a 40% average test over a 70% average any day. There's more room to beat the deviation on the high side and to me it's less stressful knowing I only have to finish 2 of the 4 questions.

-UGNG

tl;dr: keep calm and carry on

Yeah, low averages are pretty standard. In my Physics II class freshman year we had a 20-something average on one exam, and the P-Chem exam we got back today had an average around 60% (the prof hasn't given us the curve yet, just said the average was well under 70%) with a minimum passing grade of 40%. It's not about doing well, just doing better than everyone else. It's a silly system, in my opinion, but it is what it is, I guess.
Though I don't see how 70% can be too high...that's what the averages are supposed to be by the letter-grade system.

[Winter_Wolf]

*snipped*
Though I don't see how 70% can be too high...that's what the averages are supposed to be by the letter-grade system.

In the US 70% is average, i.e. "demonstrates a basic level of competence in the area", but in China for example, 60% is good enough. Or as my history professor would say, "A 'C' grade (70%) is what you get from me if you can demonstrate that you've learned and can (essentially) parrot back what you're supposed to have learned. A 'B' grade (80%) represents that plus critical thinking skills allowing you to connect some dots." She never said much about 'A' grades (90%+) because presumably no one has ever gotten one. I'd extrapolate that her criteria for an 'A' are all of the above plus you've blown her mind with your brilliant logic and ability to extrapolate and synthesize ground breaking ideas. Given that she was almost as old as dirt, I gather that no one of typical college age had the capacity to even make her raise an eyebrow, let alone blow her mind.

Back from that tangent, I don't know why you'd have to make exams harder for mathematics if they were fair and meant to test students' ability to demonstrate their retention and understanding of the materials taught. Some profs seem to take an unnatural delight in just requiring a certain percentage of students to fail, no matter how well the class as a whole grasps a concept. At my school, "grading on the curve" went essentially like this: If the curve is set at 80% by the students' performance and you are the lowly 75%, you fail, because you're on the low side of the bell rather than because you can't demonstrate a basic proficiency.

[Zahhak]

My trig prof was like that (I'm a newb math major). There were four tests. First one he said the class average was 60%. Next test, 70%, and some comment about us making good progress. Third test, he said it was "70%, right where it should be". My first thought was "yeah, bull**** 70% in a freshmen level course". One of the other guys in the class talked to most of the other students, and found that of the like 12 of us, atleast 9 failed. One guy got like a 30%. **** was brutal, and now I think he was lying about the class averages.

[noparlpf]

Got my US History exam back today. It's a 100-level freshman class, US history from "discovery" up through the end of the Civil War. For this exam, 30% was enough to pass. :smallsigh:

[warty goblin]

This is why people who don't know statistics shouldn't use them.

The mean is very sensitive to extreme values. You can get a mean of seventy when most people are scoring under forty, or even lower. The average is only a good measure of central tendency when the distribution is relatively symmetrical. If your distribution is skewed, the median is a better measure of central tendency.

Secondly, making the test harder doesn't, on its own, mean that you can better separate the good from the average students. In order to do that you need a strongly right skewed distribution of scores - so relatively few people getting very high scores and most people scoring fairly low. Just making the test harder without careful design has a good chance of simply being so long or so hard that you take the original test distribution and shift it down.

Thirdly, and non-statistically, at least in the undergrad math I did, means in the seventies were pretty common. Hell, I'm a graduate student studying statistics now, and means or medians in the seventies still aren't uncommon. And they don't joke around with grad level exams. Also you haven't really seen summary statistics for an exam until you've seen summary statistics for a stat exam.

Fourthly, isn't the better question whether or not doing well on the test required actually understanding the material to the degree required by the class?