[R] powerTransform warning message?

[Brittany Demmitt]

Hello,

I have a series of 40 variables that I am trying to transform via the boxcox method using the powerTransfrom function in R.  I have no zero values in any of my variables.  When I run the powerTransform function on the full data set I get the following warning. 

Warning message:
In sqrt(diag(solve(res$hessian))) : NaNs produced

However, when I analyze the variables in groups, rather than all 40 at a time I do not get this warning message.  Why would this be? And does this mean this warning is safe to ignore?

I would like to add that all of my lambda values are in the -5 to 5 range.  I also get different lambda values when I analyze the variables together versus in groups.  Is this to be expected?

Thank you so much!

Brittany
	[[alternative HTML version deleted]]