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From: JosephKK on 20 Jul 2010 07:12
On Fri, 16 Jul 2010 13:27:45 -0700, Tim Wescott <tim(a)seemywebsite.com>
wrote:

>On 07/16/2010 12:13 PM, Michael Robinson wrote:
>>> They're really just wording the question kinda poorly (and they're also
>>> assuming the student population is very, very large -- as you point out,
>> if
>>> there are only 100 kids at the school, you can come up with very
>> definitive
>>> answers). What they really mean is something like:
>>>
>>> -- You're performing sampling where 45% of the time you get answer A
>> (someone
>>> votes for the underdog), and 55% of the time you get answer B (a vote for
>> the
>>> other guy). If you perform 100 random samples, what's the likelihood that
>>
>>> you'll get more than 50 'A' answers?
>>>
>>> This is a standard statistics question, along the lines of, "If you roll a
>>
>>> fair dice 100 times, what's the likelihood you'll get '3' 20 or more
>> times?"
>>>
>>> Part of engineering is figuring out what your "customer" really wants when
>>
>>> their own description is kinda flaky. :-)
>>>
>>> ---Joel
>>>
>>>
>> If the school population is many, many magnitudes larger than the number of
>> voters, the chance that underdog will win just reduces to 45% (the same as
>> the underdog's chance of winning if only one student votes).
>> And in the case where the school population is relatively small, the
>> simulation methodology suggested is so bad it's not even wrong. Sampling
>> will always return about 45%, and we have seen that the chances of the
>> underdog winning can range as low as zero. The exercise is meaningless.
>> I think I should go for a walk.
>
>Uh, no.
>
>The probability distribution of the resulting vote is a binomial
>distribution (http://en.wikipedia.org/wiki/Binomial_distribution), with
>a peak at 55 votes for the winner and 45 votes for the loser. It'll
>have a variance of 100 * 0.45 * 0.55 = 24.75. With that many votes
>it'll be pretty close to a normal distribution, so the probability that
>a vote will go the wrong way is about 16%.
>
>So when you get back from your walk, you probably want to brush up on
>your statistics.
>
>Doing this by simulation makes no sense unless the aim of the exercise
>is to teach the student how to do Monte Carlo simulation, or to help
>them get a feel for that 16% probability of a wrong vote.

Aw phooey. The student was supposed to bump their nose up against
that, hard. It is one of those lessons that the only real way to
learn it is to bump up aginst it the hard way.
From: Richard Henry on 20 Jul 2010 19:34
On Jul 16, 1:39 pm, Joerg <inva...(a)invalid.invalid> wrote:
> Joel Koltner wrote:
> > "Joerg" <inva...(a)invalid.invalid> wrote in message
> >news:8abmkrFbojU1(a)mid.individual.net...
> >> One question I always pondered is, why are they teaching this in
> >> engineering school anyhow?
>
> > Some EE ends up using it? :-)
>
> > Stats show up an awful lot in...
>
> > -- Communication texts, worrying about the effect of nose on signal
> > intelligibility --> Those trying to cook up new modulation formats
> > should worry about this
> > -- Error-correcting codes --> Those worrying about choosing
> > error-correctoin schemes should worry about it
> > -- Phil Hobbs' book :-)
> > -- Tim Wescott's book :-)
>
> Also Monte Carlo in SPICE, named after _the_ casino city. Actually,
> formally it's a whole country unto itself.
>
> > I think the real answer is that curriciulums often have historical roots
> > that are hard to change even when the material becomes of margin use for
> > most students.  Many a practicing BSEE can do just fine recalling no
> > more statistics than, e.g., how to calculate a mean...
>
> Ok, yes, I agree that we all need it. My point really was, isn't this
> sort of stuff the job of a high school to teach? There has got to be a
> reason why we all must go to high school before heading towards
> engineering :-)
>
> --
> Regards, Joerg
>
> http://www.analogconsultants.com/
>
> "gmail" domain blocked because of excessive spam.
> Use another domain or send PM.

The casino is Monte Carlo, which is a small part of the small country
of Monaco.
From: Richard Henry on 20 Jul 2010 19:38
On Jul 16, 2:54 pm, "Michael Robinson" <kellrobin...(a)yahoo.com> wrote:
> "Tim Wescott" <t...(a)seemywebsite.com> wrote in message
>
> news:YeOdnX2xNNIGXd3RnZ2dnUVZ_qednZ2d(a)web-ster.com...
>
> > On 07/16/2010 12:13 PM, Michael Robinson wrote:
> >>> They're really just wording the question kinda poorly (and they're also
> >>> assuming the student population is very, very large -- as you point out,
> >> if
> >>> there are only 100 kids at the school, you can come up with very
> >> definitive
> >>> answers).  What they really mean is something like:
>
> >>> -- You're performing sampling where 45% of the time you get answer A
> >> (someone
> >>> votes for the underdog), and 55% of the time you get answer B (a vote
> >>> for
> >> the
> >>> other guy).  If you perform 100 random samples, what's the likelihood
> >>> that
>
> >>> you'll get more than 50 'A' answers?
>
> >>> This is a standard statistics question, along the lines of, "If you roll
> >>> a
>
> >>> fair dice 100 times, what's the likelihood you'll get '3' 20 or more
> >> times?"
>
> >>> Part of engineering is figuring out what your "customer" really wants
> >>> when
>
> >>> their own description is kinda flaky. :-)
>
> >>> ---Joel
>
> >> If the school population is many, many magnitudes larger than the number
> >> of
> >> voters, the chance that underdog will win just reduces to 45% (the same
> >> as
> >> the underdog's chance of winning if only one student votes).
> >> And in the case where the school population is relatively small, the
> >> simulation methodology suggested is so bad it's not even wrong.  Sampling
> >> will always return about 45%, and we have seen that the chances of the
> >> underdog winning can range as low as zero.  The exercise is meaningless.
> >> I think I should go for a walk.
>
> > Uh, no.
>
> > The probability distribution of the resulting vote is a binomial
> > distribution (http://en.wikipedia.org/wiki/Binomial_distribution), with a
> > peak at 55 votes for the winner and 45 votes for the loser.  It'll have a
> > variance of 100 * 0.45 * 0.55 = 24.75.  With that many votes it'll be
> > pretty close to a normal distribution, so the probability that a vote will
> > go the wrong way is about 16%.
>
> You can get an exact answer using the binomial distribution only in trials
> with replacement. This problem descirbes trials without replacement.
>
> If you use the binomial distribution here you will get an approximation.
>
> If the school population is very large, then the approximation would be a
> good one because the trial will be close to one with replacement -- in other
> words, you'll seldom count a student twice when you do your sampling of 100
> out of a much larger population.
>
> The simple fact is that the book's naively constructed simulation solution
> will give an answer that approaches validity only assuming very large school
> population (and there's no point in doing a sim then because you already
> know the answer).
>
> For any school population where the outcome is worth calculating -- say, a
> few hundred students -- the suggested sim is dead wrong. The "underdog's"
> chance of winning varies. Always less than 45%, approaching zero as the
> school pop approaches 109 or 108. While the sim always returns values
> centering around 45%.
>
> Now can you see why I said it's a dumb problem?
>
> > So when you get back from your walk, you probably want to brush up on your
> > statistics.
>
> > Doing this by simulation makes no sense unless the aim of the exercise is
> > to teach the student how to do Monte Carlo simulation, or to help them get
> > a feel for that 16% probability of a wrong vote.
>
> > --
>
> > Tim Wescott
> > Wescott Design Services
> >http://www.wescottdesign.com
>
> > Do you need to implement control loops in software?
> > "Applied Control Theory for Embedded Systems" was written for you.
> > See details athttp://www.wescottdesign.com/actfes/actfes.html
>

Got an F on the assignment?
From: Joerg on 24 Jul 2010 16:03
Richard Henry wrote:
> On Jul 16, 1:39 pm, Joerg <inva...(a)invalid.invalid> wrote:
>> Joel Koltner wrote:
>>> "Joerg" <inva...(a)invalid.invalid> wrote in message
>>> news:8abmkrFbojU1(a)mid.individual.net...
>>>> One question I always pondered is, why are they teaching this in
>>>> engineering school anyhow?
>>> Some EE ends up using it? :-)
>>> Stats show up an awful lot in...
>>> -- Communication texts, worrying about the effect of nose on signal
>>> intelligibility --> Those trying to cook up new modulation formats
>>> should worry about this
>>> -- Error-correcting codes --> Those worrying about choosing
>>> error-correctoin schemes should worry about it
>>> -- Phil Hobbs' book :-)
>>> -- Tim Wescott's book :-)
>> Also Monte Carlo in SPICE, named after _the_ casino city. Actually,
>> formally it's a whole country unto itself.
>>
>>> I think the real answer is that curriciulums often have historical roots
>>> that are hard to change even when the material becomes of margin use for
>>> most students. Many a practicing BSEE can do just fine recalling no
>>> more statistics than, e.g., how to calculate a mean...
>> Ok, yes, I agree that we all need it. My point really was, isn't this
>> sort of stuff the job of a high school to teach? There has got to be a
>> reason why we all must go to high school before heading towards
>> engineering :-)
>>
>> --
>> Regards, Joerg
>>
>> http://www.analogconsultants.com/
>>
>> "gmail" domain blocked because of excessive spam.
>> Use another domain or send PM.
>
> The casino is Monte Carlo, which is a small part of the small country
> of Monaco.


Huh? Small? Monte Carlo and La Condamine are pretty much grown together.
What's left is a little area called Fontvieille in the south and AFAIK
there ain't much in the north. And that's pretty much it.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: Richard Henry on 24 Jul 2010 17:23
On Jul 24, 1:03 pm, Joerg <inva...(a)invalid.invalid> wrote:
> Richard Henry wrote:
> > On Jul 16, 1:39 pm, Joerg <inva...(a)invalid.invalid> wrote:
> >> Joel Koltner wrote:
> >>> "Joerg" <inva...(a)invalid.invalid> wrote in message
> >>>news:8abmkrFbojU1(a)mid.individual.net...
> >>>> One question I always pondered is, why are they teaching this in
> >>>> engineering school anyhow?
> >>> Some EE ends up using it? :-)
> >>> Stats show up an awful lot in...
> >>> -- Communication texts, worrying about the effect of nose on signal
> >>> intelligibility --> Those trying to cook up new modulation formats
> >>> should worry about this
> >>> -- Error-correcting codes --> Those worrying about choosing
> >>> error-correctoin schemes should worry about it
> >>> -- Phil Hobbs' book :-)
> >>> -- Tim Wescott's book :-)
> >> Also Monte Carlo in SPICE, named after _the_ casino city. Actually,
> >> formally it's a whole country unto itself.
>
> >>> I think the real answer is that curriciulums often have historical roots
> >>> that are hard to change even when the material becomes of margin use for
> >>> most students.  Many a practicing BSEE can do just fine recalling no
> >>> more statistics than, e.g., how to calculate a mean...
> >> Ok, yes, I agree that we all need it. My point really was, isn't this
> >> sort of stuff the job of a high school to teach? There has got to be a
> >> reason why we all must go to high school before heading towards
> >> engineering :-)
>
> >> --
> >> Regards, Joerg
>
> >>http://www.analogconsultants.com/
>
> >> "gmail" domain blocked because of excessive spam.
> >> Use another domain or send PM.
>
> > The casino is Monte Carlo, which is a small part of the small country
> > of Monaco.
>
> Huh? Small? Monte Carlo and La Condamine are pretty much grown together.
> What's left is a little area called Fontvieille in the south and AFAIK
> there ain't much in the north. And that's pretty much it.
>
> --
> Regards, Joerg
>
> http://www.analogconsultants.com/
>
> "gmail" domain blocked because of excessive spam.
> Use another domain or send PM.

ccording to the CIA World Factbook

https://www.cia.gov/library/publications/the-world-factbook/geos/mn.html

Monaco contains only one city, named Monaco, which encompasses all the
area of the country. Monte Carlo is an administrative division
(quartier) of that city/country.
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