Re: math question verrrrrry off topic
Ian,
may be it's just a typo but C(n,m) =
600!
-------------------
150!(600-150)!
=
1277916851111034312174368668471297860116606752864715959921012222958747794594
5942798968735988572227507979644437906069421788093063476741931161574096
I t is however way much larger then what usual software can endle and this
is why I said it's infinite. Still remains the problem that somewhere in
these gazillion sets of 150 are our 3 people from institution A.
Yves
----- Original Message -----
From: "Iain" <iain.coghill@eiflex.com>
To: <alt-photo-process-l@usask.ca>
Sent: Saturday, January 19, 2008 12:56 PM
Subject: Re: math question verrrrrry off topic
> There are actually 600!/(600 - 150)! ways to randomly pick 150 items
> from a bag of 600, where n! (pronounced n-factorial) is defined as 1 x 2
> x 3 x ... x (n-1) x n. If you don't care about which order those 150 are
> picked you can divide that number by 150! - giving roughly 57 followed
> by 261 zeroes
>
> Yves Gauvreau wrote:
> > Hi,
> >
> > if one consider the number of ways to pick randomly 150 items in a bag
with
> > 600 items in it, then the answer is infinity and whatever you do after
that
> > like multiplying it by a tiny tiny tiny probability, even then your
stock
> > with infinity.
> >
> > One would need to approach this problem another way and in our case the
150
> > people are not choosen randomly in practice. The only other way around
to
> > give an answer to Chris, is to find out what's in the bag. For example,
say
> > we fill the bag with 10 oranges and ask someone to pick 3 items in that
bag,
> > what is the probability of getting 3 oranges. 100% of course but if the
bag
> > contains 3 oranges, 4 bananas and 3 pear, the answer is différent of
course.
> > All this to say we need to know what's in the bag.
> >
> > Regards,
> > Yves
> >
> >
> >
> > ----- Original Message -----
> > From: "Katharine Thayer" <kthayer@pacifier.com>
> > To: <alt-photo-process-l@usask.ca>
> > Sent: Saturday, January 19, 2008 9:51 AM
> > Subject: Re: math question verrrrrry off topic
> >
> >
> >
> >> Okay, look.
> >>
> >> If this were a simple probability experiment, let's say there were
> >> 600 objects in a big jar, all exactly the same size and shape and
> >> differing only in color: 450 red ones (for not-accepted) and 150
> >> green ones (for "accepted") all mixed up really well, and the
> >> question was, "if some people from College X reached into the jar
> >> blindfolded and three of them pulled out green objects, what would
> >> the probability of that result be, would it be 1/4x1/4x1/4?" then
> >> the answer would be "only if just three people from College X
> >> reached into the jar. If more than three people from college x
> >> reached into the jar, let's say five people from college x reached
> >> into the jar, then the probability of three of those five people
> >> pulling out a green marble would be 1/4 x 1/4 x 1/4 x 3/4 x 3/4."
> >>
> >> But of course this isn't anything like that. In this case, the 600
> >> objects in the jar are made by the people who are being selected, and
> >> the objects are all different, all different sizes and shapes and
> >> colors, and made of different materials. People might contribute
> >> different numbers of objects (though it's never been clear to me
> >> whether that's the case or not) in which case the objects made by the
> >> same person presumably aren't as different from each other as the
> >> objects made by different people. And the selection is made not by
> >> the people themselves reaching into the jar blindfolded, but by a
> >> third party, a judge, who also doesn't reach into the jar blindfolded
> >> and pull out objects randomly to make a selection, but pours them all
> >> out on in a big tray and looks at all 600 of them closely before
> >> deciding which ones he/she wants to include. This particular judge
> >> might be drawn to metal objects, or even especially to platinum over
> >> silver, or maybe he or she particularly dislikes street scenes and
> >> prefers pictures of old mills, or is looking for a certain level of
> >> craftsmanship in the work, or maybe the criterion is something even
> >> more difficult to articulate, whether the judge "likes" something or
> >> not. Whatever the criteria, by the end of the day, the objects are
> >> separated into two piles, "accepted" and "not accepted," and there
> >> are 150 objects in the first pile and 450 in the second pile.
> >>
> >> I hope it should be clear to everyone at this point how different
> >> this is from the problem above, and why you can't treat this as a
> >> problem of simple probability and say that the probability of any
> >> entry being accepted is the same as the probability of any other
> >> entry being accepted, and that this equal probability for each entry
> >> is 1/4, since 1/4 of all the entries were accepted. It's just not
> >> that kind of problem, and it doesn't work to treat it that way.
> >> Thank you.
> >> Katharine
> >>
> >>
> >>
> >>
> >> On Jan 18, 2008, at 6:49 PM, Katharine Thayer wrote:
> >>
> >>
> >>> :--)
> >>>
> >>>
> >>> On Jan 18, 2008, at 6:23 PM, Diana Bloomfield wrote:
> >>>
> >>>
> >>>
> >>>> Hey Katharine,
> >>>>
> >>>> I don't know-- maybe. I honestly didn't read the other answers. :)
> >>>>
> >>>>
> >>>> On Jan 18, 2008, at 8:43 PM, Katharine Thayer wrote:
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> Hmm, I thought that's what we all already have said, isn't it?
> >>>>> That that theoretical probability (1/4x1/4x1/4) would hold only
> >>>>> if assumptions were met, and since assumptions are obviously not
> >>>>> met (for example, judging is not a random lottery of course but
> >>>>> is done on the basis of criteria, arbitrary or otherwise but
> >>>>> certainly not random). Also, no one has said whether the 600
> >>>>> entries are 600 works or 600 people; I was assuming that they are
> >>>>> 600 works representing fewer than 600 people, in other words
> >>>>> people could submit more than one work, in which case, as I said,
> >>>>> the number of works submitted per person would also have to be
> >>>>> figured into the equation somehow. Besides, if one person
> >>>>> submits ten pieces and another person submits one, the ten pieces
> >>>>> by the one person couldn't be considered independent entries in
> >>>>> the same way one of those ten could be considered independent of
> >>>>> the one from the other person, and independence is also an
> >>>>> assumption that must be met in order to consider the probability
> >>>>> of acceptance to be the same for all entries.
> >>>>> Katharine
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Jan 18, 2008, at 4:25 PM, Diana Bloomfield wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> Okay, Chris. Here is it-- straight from my resident
> >>>>>> statistician here:
> >>>>>>
> >>>>>> If they were the only 3 people from that institution who
> >>>>>> applied, AND if judging was completely random, then the
> >>>>>> probability of this is roughly 1 in 64 (key word: roughly). If
> >>>>>> more than that applied from this same institution, and only 3
> >>>>>> got in, then the calculation will be more complex.
> >>>>>>
> >>>>>> Hope that helps. :)
> >>>>>> On Jan 17, 2008, at 12:00 PM, Christina Z. Anderson wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> Where else but this list can I ask these weird questions about
> >>>>>>> chemistry and math and computers and alt???
> >>>>>>>
> >>>>>>> OK for you math people (Yves?): If there is a show and 600
> >>>>>>> entries, and 150 are accepted, there is a 1 in 4 chance of
> >>>>>>> acceptance. If 3 people from the same institution are accepted
> >>>>>>> what percent chance is that--is it 1/4 x 1/4 x 1/4 or a 1.5%
> >>>>>>> chance or is it a more complex formula?
> >>>>>>>
> >>>>>>> Forgive the off topic request but it does relate to photo as 3
> >>>>>>> of our program got into a photo show and I want to be able to
> >>>>>>> mathematically brag about it to the dept. head/dean.
> >>>>>>> Chris
> >>>>>>>
> >>>>>>> Christina Z. Anderson
> >>>>>>> Assistant Professor
> >>>>>>> Photo Option Coordinator
> >>>>>>> Montana State University
> >>>>>>> CZAphotography.com
> >>>>>>> _______________
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>
> >
> >
> >
> >
> >
> >
> >
>