I think this will do it, though there might be a simpler way
for(j in 1:50{
for (i in 1:4000){
ind[i,j] <- equals(group[i],j)
wtd_pred[i,j] <- ind[i,j]*pred[i]
}
mean_pred[j] <- sum(wtd_pred[,j])/sum(ind[,j])
}
Best wishes
Andrew
--
Dr. Andrew Millard
e: [log in to unmask] | t: +44 191 334 1147
w: http://www.dur.ac.uk/archaeology/staff/?id=160
Senior Lecturer in Archaeology, & Associate Director
of the Institute of Medieval & Early Modern Studies,
Durham University, UK
> -----Original Message-----
> From: (The BUGS software mailing list) [mailto:[log in to unmask]] On
> Behalf Of Basile Chaix
> Sent: 24 September 2015 20:08
> To: [log in to unmask]
> Subject: [BUGS] Calculation of an average by group in Winbugs
>
> Dear colleagues,
>
> In my Winbugs model, I have a variable, eg for 4000 observations
> reporting group membership, and there are 50 groups coded from 1 to 50
> in this variable. The variable is group[i] with i from 1 to 4000.
>
> From my model, I calculate a predicted value, pred[i], with i from 1
> to 4000.
>
> I simply want to calculate at each iteration the mean value of pred
> for each of the 50 groups of the group variable. The mean of the
> prediction by groups will be mean_pred[j] with j ranging from 1 to 50
>
> How to calculate mean_pred[j] from pred[i] and group[i]?
>
> Thank you so much for your help,
>
> Basile
>
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-------------------------------------------------------------------
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