Apologies! That is what I meant (I think). Anyone who knows me will
tell you that maths (especially equations) is far from my strong point.
Perhaps that is why I am having trouble getting my head round things?!
Samantha
-----Original Message-----
From: Kevin Ashley [mailto:[log in to unmask]]
Sent: 25 November 2005 11:57
To: Farhall Samantha
Subject: Re: Estimating staff time needed for cataloguing
Farhall Samantha wrote:
> Thank you very much to everyone who replied to my request for help
> estimating staff time needed for cataloguing. Several people have
asked
> for the results, so here is a summary:
.....
>
> * Work out the most optimistic time (O), the most pessimistic time
> (PS) and the probable time (PR): O + (4 x PR) + PS / 6 = time
taken
I suspect that the formula should read:
( O + (4 x PR) + PS ) / 6 = time taken
That will give a weighted average of the estimates which will always
result in a time slightly longer than the probable time. As you
wrote it, the pessimistic time is divided by 6 before doing the
addition, and for many values of PR and PS this could result in
an answer much worse than the pessimistic time!
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