Let's think a little bit about what you want to do with the results.

Suppose you had data on all 130 projects.  Presumably there would be no
'error,' true?  But you just defined your population as all 130
projects.  Therefore, any conclusions you draw apply only to those 130.
You cannot make any projections toward behavior of the next projects
undertaken.

Is this what you want?  I doubt it.  Not particularly useful to discuss
only what was already complete.

Suppose you define your population as "all the projects that were or can
be performed by this one corporation, using the conditions that have
applied in the past (whatever conditions influence the part of the
project you are measuring and analyzing.)  Now the population is
infinite, and there is no FPC factor to worry about.

And, you can use your conclusions to predict how projects will run in the
future.  If I were a manager in that firm, I'd want to know this a heck
of a lot more than how the completed projects went.  I mean, I can look
at those old ones all I want - they are done and gone.

Does this help you any?

Jay

Mats Lingblad wrote:

> I have data on 70 out of 130 projects completed in one firm. What is
> the correct way to think about the the standard errors in regression
> analysis, if I want to generalise to the firm?
> 1. Adjust with the FPC factor since a large portion of the population
> is covered.
> 2. Do not adjust with the FPC factor since it is the potential number
> of projects started by the firm that constitute the "true" population.
>
> Alternative 2 is safer and more conservative, but it also seems a bit
> too hard since the large n/N ratio should count for something.
>
> I would also appreciate it if somebody has references on this subject.
>
> Finally does anyone have the formula for adjusting the F-test in
> standard OLS regression models for a finite population?
>
> Regards,
>
> Mats Lingblad
> LBS
> London
> .
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--
Jay Warner
Principal Scientist
Warner Consulting, Inc.
4444 North Green Bay Road
Racine, WI 53404-1216
USA

Ph: (262) 634-9100
FAX: (262) 681-1133
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