July 11, 2003

Precision of Language

Precision of language is important:

Uncertain Principles: Vaguely Relevant Geek Joke: A colleague mentioned seeing an oral exam in which a student worked through a derivation on the chalkboard, and ended up with has answer having the wrong sign. "I seem to have made a sign error," he said. "No," corrected one of his professors, "you seem to have made an odd number of sign errors."

Posted by DeLong at July 11, 2003 10:50 AM | TrackBack

Comments

Allow me to seize the occasion of this post on language, which involves words, to call attention to the appalling plight of the North Atlantic Sea Owl, which is four words. There, I feel better now.

Posted by: John Isbell on July 11, 2003 12:59 PM


Ah - truly a joke only an economist could love.

It reminds me of Gilbert Ryle's insightful observation that most humor was based on category mistakes.

sz

Posted by: SZ on July 11, 2003 01:24 PM

"Ah - truly a joke only an economist could love."

Not so: it has a clear appeal for the mathematicians' contingent as well (perhaps even primarily for that contingent).

Posted by: Abiola Lapite on July 11, 2003 03:41 PM

Two mathematicians were having dinner in a restaurant, arguing about the mathematical knowledge of the average American. One mathematician claimed that the average was woefully inadequate, the other maintained that it was surprisingly high.

"I'll tell you what," said the cynic, "ask that waitress a simple math question. I'll bet you dinner she won't get it right. If I'm wrong, I'll pick up dinner. If not, it's yours." He then excused himself to visit the men's room, and the other called the waitress over.

"When my friend comes back," he told her, "I'm going to ask you a question, and I want you to respond `one third x cubed.' There's twenty bucks in it for you if you get it right." She agreed.

When the cynic returned from the restroom the other mathematician called the waitress over. "The food and service were both excellent, thank you," he said. "Maybe you can help me with one other thing: do you know what the integral of x squared is?"

The waitress looked pensive, almost pained. She looked around the room, stared at her feet, made a murmuring noise, and finally replied, "Um, one third x cubed?"

After the cynic paid the check, the waitress abruptly turned around, walked a few paces, looked back at the two men, shook her head, and muttered under her breath, "...plus a constant."

Posted by: consigliere on July 11, 2003 04:26 PM

Of course, if you wanted to be pedantic (which seems appropriate in this context) the professor is making an unwarranted assumption that sign errors always cancel each other. The student could have made a sign error inside of an absolute value, for example, which would not affect the final result. In that case, he could have made an even number of sign errors.

The student's original claim is closer to the truth. He made an error. He might have made several errors, but he definitely made one. He assumes it was a sign error, but it could have been an entirely different error.

(Sorry, I think I would have kept quiet except for the "plus a constant" joke. I also think this probably appeals more directly to mathematicians than economists but I'm not as certain about what economists find funny.)

Posted by: Paul Callahan on July 11, 2003 06:12 PM

sz, re: joke only an economist could love.

I'm an electrical engineer and LOL. My soon-to-be-wife (the English teacher) didn't get it. That's OK, I'm sure you could send a slew of Shakespeare jokes under my nose and I'd never know it.

Posted by: Stoffel on July 11, 2003 07:46 PM

Somewhere in the middle of a complicated differential equations question I made a sign error and ended up with an answer that was way off. But the methodology of my approach was correct, so I argued that I should receive more partial credit that the professor assigned.

After looking over my work a second time, he agreed to add 6 more points and proceeded to subtract the points from my score…

Posted by: Rob Sperry on July 11, 2003 11:23 PM

The joke depends on the correction being right, but it's not. Surely (what's here meant by)an 'even number of sign errors' entails a non-erroneous answer.

Posted by: Jimmy Doyle on July 12, 2003 06:36 AM

The joke depends on the correction being right, but it's not. Surely (what's here meant by)an 'even number of sign errors' entails a non-erroneous answer.

Posted by: Jimmy Doyle on July 12, 2003 06:37 AM

The joke depends on the correction being right, but it's not. Surely (what's here meant by)an 'even number of sign errors' entails a non-erroneous answer.

Posted by: Jimmy Doyle on July 12, 2003 06:38 AM

But don't 2 negative signs still make a positive sign, and you could still get the right answer as long as you group the factors correctly? As long as the signs are in the right places.

Posted by: nothernLights on July 12, 2003 07:04 AM

Let me point out that my non sequitur opening comment referred to three long non sequitur extracts about Iraq which Brad understandably deleted.

Posted by: John Isbell on July 12, 2003 12:58 PM
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