I have a question about nlme (and yes, I have a copy of "Mixed-Effects Models in S and S-Plus" on order :-)
I have a data frame, df, that I use to create a groupedData object: > df.K1 <- groupedData(K1 ~ tissue.ROI | scan, data=df ) If I add an outer grouping factor, I get a warning: > df.K1 <- groupedData(K1 ~ tissue.ROI | scan, data=df, outer=~input.ROI ) Warning message: argument lengths differ in: split(x, f) Can anyone help me understand where this warning message is coming from? And what I might make of it? Thanks, Mike -- Michael A. Miller [EMAIL PROTECTED] Imaging Sciences, Department of Radiology, IU School of Medicine ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
