[R] question on xyplot

eugen pircalabelu eugen_pircalabelu at yahoo.com
Fri Oct 3 15:04:02 CEST 2008

Hi List,

I have the following problem: I am using the multilevel package and make.univ function for available in the package and then xyplot from lattice and I want to know how could I be able to use the “coefficient” for the straight line that passes the data ?

Example from help:

data(univbct)  #a data set already in univariate or stacked form for job satisfaction
TEMP<-univbct[3*1:495,c(22,1:17)]  #converting it back to multivariate form
TEMP2<-make.univ(x=TEMP,dvs=TEMP[,c(10,13,16)])  #transforming it to univariate form again

xyplot(MULTDV~TIME|as.factor(SUBNUM),data=TEMP2,type=c("p","r","g"),col="blue",col.line="black",xlab="Time",ylab="SAT") # taken from Bliese Paul – Multilevel Modeling in R

Now I want to be able to identify those SUBNUM that have a downwards trend like (for eg SUBNUM 7) without picking them by inspecting the plot. Is there some way how I could access these coefficients for this apparently regression line?

Thank you very much and have a great day ahead!
Eugen Pircalabelu

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