In Vitro Fertilization Probabilities w/ Binomial Expansion: HELP HELP!!!

Jan. 20th, 2009 @ 10:30 pm


 From:  digitig 

Date:  January 21st, 2009 10:29 am (UTC) 

  Re: Independent Eggs  (Link) 

I once saw an online lecture about teaching probability through surprising results, and the lecturer said that it's almost impossible to teach probability to engineers, since they've taken a little calculus and think they know everything. I think the lecturer meant "because their brains are already full" :) I find it a strange claim, actually, because engineers have to work a lot with probability nowadays, and they'd struggle to qualify as engineers if they didn't understand probability at least reasonably well. Perhaps the lecturer was making the common mistake in the English speaking world of confusing technicians with engineers. Or maybe they were thinking of oldschool engineers who were much more about making and much less about analysis. Why, yes, I am an engineer as it happens...    Re: Independent Eggs  (Link) 

...they'd struggle to qualify as engineers if they didn't understand probability at least reasonably well. Taking stats courses doesn't mean they understand the subject. See ITE Code 814 for reference: the "bible" of traffic engineering is risking people's lives on the basis of a comically bad regression.  From:  digitig 

Date:  January 21st, 2009 03:13 pm (UTC) 

  Re: Independent Eggs  (Link) 

I've no idea what ITE Code 814 is or where I might see it, but I have seen some appalling probability blunders written into regulations by bureaucrats (and I've been in a standardisation meeting where the chair insisted that the question of whether a pure Poisson process is time stationary be put to a vote, rather than just checking any elementary textbook)  and I've seen the engineers lumbered with implimenting those regulations wince, because they realise that they'll have to do every job twice: once the right way so that things work, and again the wrong way to satisfy the regulators. Duff standards doesn't tell you whether engineers understand probability, it tells you which engineers can most readily be spared from their normal work to sit on the committees.    Re: Independent Eggs  (Link) 

...and I've been in a standardisation meeting where the chair insisted that the question of whether a pure Poisson process is time stationary be put to a vote.... That's insane. [pissy, grumpy mode] I'd be more sympathetic if I weren't dealing with a shoppingcenter application where the traffic engineer is trying to help the developer kill people by basing designs on a traffic volume regression of four data points, three of which are dominated by an outlier. Honestly, it beggars belief — talk some sense into traffic engineers for me, will 'ya? Here's how it works for them. Choose a land use. Then sit and count peakhour traffic for that land use. Do that a few times and run a regression of traffic against size on those results. Now the coefficient on size becomes a strictly deterministic Fact, with a capital eff, and is treated as such. [/pissy, grumpy mode] Anywho, be well!  From:  digitig 

Date:  January 21st, 2009 04:45 pm (UTC) 

  Re: Independent Eggs  (Link) 

Honestly, it beggars belief — talk some sense into traffic engineers for me, will 'ya? Here's how it works for them. Choose a land use. Then sit and count peakhour traffic for that land use. Do that a few times and run a regression of traffic against size on those results. Now the coefficient on size becomes a strictly deterministic Fact, with a capital eff, and is treated as such. Well, of course, it is a strictly deterministic fact, the question is, what fact? For one thing, it's an expected value of the coefficient on size, which will have confidence bounds (I've often thrown people who insist I demonstrate that the probability of an undesired event is less than some specified value into a spin by asking them "to what confidence do I need to demonstrate it?") And it's the expected value at the times the observation was made  is it subject to diurnal or seasonal variation? And so on. But it is a strictly deterministic fact, just not the one that they want. Anyway, we seem to have strayed from probability into statistics :)    Re: Independent Eggs  (Link) 

Have you heard about the engineer who lived around the time of the French Revolution? People who felt they were being guillotined unjustly would lie down facing upward, and if the guillotine didn't work, it was considered providence of God and they were spared. So when an unjustly condemned engineer followed a few people who were spared, he looked up at the mechanism, saw what was wrong with it, and explained how to fix it...  From:  digitig 

Date:  January 21st, 2009 06:09 pm (UTC) 

  Re: Independent Eggs  (Link) 

That "engineer" would be Malabonce in the 1966 Carry On film "Don't Lose Your Head", wouldn't it?    Re: Independent Eggs  (Link) 

I couldn't say. My uncle, an engineer, told me the story when I was a little kid, and I think it was supposed to illustrate the ethos of the engineer.

