Displaying 2 results from an estimated 2 matches for "diagnoal".
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diagnal
2004 Nov 03
2
how to compute condition index?
is there any existing function for computing condition index?
" analysing multivariate data" say that we can use condition index to check
multicollinearity.saying that we can get it via SVD. The elements of the
diagnoal matrix are the standard deviations of the uncorrelated vectors. the
condition index is the ratio of the largest of these numbers to the smallest.
so if i have a data frame a,containg variables x,y,z.
my model is :
model<-lm(y~x+z,data=a)
so use the following to compute the condition index,but i...
2010 Feb 14
1
Problem with specifying variance-covariance matrix for random effects (nlme package)
Hi all,
I've been struggling with trying to specify a diagnoal matrix for linear mixed effects model. I think I've got nearly everything correct, except the following message appears:
In lme.formula(fixed = fwave ~ sex + sexXbulbar + visit + age + :
Fewer observations than random effects in all level 1 groups
Not sure if i've provided enough detai...