On 10/06/2008, at 6:08 PM, Ivan Adzhubey wrote:
Hi Rolf,
On Monday 09 June 2008 11:16:57 pm Rolf Turner wrote:
Your approach tacitly assumes --- as did the poster's question ---
that
the probability of passing an item by one method is *independent* of
whether it is passed by the other method. Which makes the methods
effectively independent of the nature of the item being assessed!
So it seems I can't just block my primary factor (QA procedure) by
nuisance
one (production line) and run Cochran test to see if effects of
primary
factor are identical for both its levels.
As far as I can see there is no way of doing anything sensible unless
you know or obtain the item by item results. There's not much you
can do (sensibly) with the summaries provided in your original posting.
Not much actual quality being assured there!
In fact, I am not interested in quality of QA procedures as much as
in how
different the results are (error component).
It still seems to me that the relevant questions, no matter how you
slice the situation, have to be expressed in terms of conditional
probabilities rather than the marginals. I.e. what's the probability
the procedure 2 passes an item given that procedure 1 has passed it?
What's the probability given that procedure 1 has failed it?
cheers,
Rolf Turner
######################################################################
Attention:\ This e-mail message is privileged and confid...{{dropped:9}}
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
