[R] Significance of differences in RMS?

[Jonas Beskow]

Greetings,

I have the following problem:
I want to compare a "parameter trajectory", i.e. a series of real 
numbers (representing equidistant samples of a time-varying parameter) 
produced by some "model", to a reference trajectory, measured from the 
real world, in order to get a rating of how good the model that produced 
the first trajectory is. Ok, so I use the RMS of the difference between 
the two trajectories at each sample.

Then I have another model, producing another trajectory, leading to 
another RMS-value. Good. Now I want to clame that the two models are 
"equally good" on the basis of the RMS-values being similar, and require 
some sort of significance test to support this claim. But I can't assume 
normal distribution in this case since the values are squared (or can 
I?) so with my limited knowledge of statistics I'm stuck...

Any help is appreciated!

regards

- Jonas

PS I apologize for posting a question entirely unrelated to R but any 
R-related answers are of course welcome!

-- 
Jonas Beskow, Ph.D.                     Tel: +46 8 790 8965
Centre for Speech Technology            Fax: +46 8 790 7854
KTH                                    beskow at speech.kth.se
SE-10044 Stockholm, Sweden        www.speech.kth.se/~beskow