Re: OT: AW: Loop Survey - Summary - post scriptum to eben

["radio radio" <radiotelevision@gmail.com>]

Huh. Interesting question, so far as I can follow it, but certainly
beyond my knowledge of statistical methods.

Eben



On 10/7/07, Rainer Thelonius Balthasar Straschill <rs@moinlabs.de> wrote:
> Eben, you said (replying to my age distribution question):
>
> > I'm not certain I understand your question about years of
> > looping experience, although you may be asking why there are
> > more people in the middle amount of years and less on the
> > extremes, which is how almost all data looks when you take a
> > survey (there is an average with most people in the middle,
> > and less people are further away from average).
>
> No, the question is more specific.
> First of all, of course you're right regarding the age of the loopers 
>(for
> which we also see some approximately Gaussian binning), but not regarding
> the years of looping experience, and I'm gonna explain why:
>
> The mathematical model for this works like this. Any looper i has 
>started at
> a point t1,i in time with looping. Now when the survey happens at t2, he
> will enter t2-t1,i as a reply to that question (which also has some
> predefined bins, namely <1, 1-3, 3-5, 5-10 and >10 to somehow stick with 
>the
> typical bins of human resource departments).
>
> You may argue that there might be some answers from people who stopped
> looping at a time t3,i<t2. But I believe that those wouldn't have 
>answered
> that survey, so it's fairly reasonable to assume that all of the loopers
> have been looping more or less all the time (at least everyone is still
> looping right now, and most of them in all of or a considerable amount of
> their current work).
>
> So what I'm looking at: how was the distribution when the people started
> looping in the past. If you model that the same number of people started
> looping every year, then after 18 years of looping, you get the 42% 
>value we
> have for the >10yrs people - but then the other bins look differently 
>(the
> 1-3 and 3-5 bins are about double the size of the <1 bin and the 5-10 
>bin is
> nearly three times as big as the 3-5 bin because these bins have 
>different
> widths). More precisely, this model gives me values 5.3, 11, 11, 32 and 
>42,
> respectively.
>
> So how has the number of loopers which joined each year in the past have 
>to
> look to lead to our distribution of 5 - 15 - 19 - 20 - 42? I did some 
>simple
> runs with the Solver in Excel, and it looks like it's a distribution with
> the first people starting more than 20 years ago, a very slow increase 
>from
> then, then some sharp peaks about 9 and 5 years ago and since then a 
>slight
> decline.
>
> However, this set of equations is underdetermined, so: with your 
>knowledge
> of statistical methods, would you be able to deduct the generating 
>function
> or parameter for a surface which describes the solutions to this set of
> equations?
>
>         Rainer
>
>