[R] Complex multiple t tests in a data frame with several id factors

I have assayed the concentrations of various metal elements in different anatomic regions of two strains of mice. Now, for each element, in each region, I want to do a t test to find whether there is any difference between the two strains. Here is what I did (using simulated data as an example):

Re: [R] Complex multiple t tests in a data frame with several id factors

The concentrations of the different metals within an animal are correlated, so that doing as you suggest will almost certainly result in nonsense P values. So I suggest you seek local statistical help or, failing that, post on a statistical forum like stats.stackexchange.com . There are various

Re: [R] Complex multiple t tests in a data frame with several id factors

Okay, thank you. On Mon, Dec 5, 2011 at 12:01 AM, Bert Gunter gunter.ber...@gene.com wrote: The concentrations of the different metals within an animal are correlated, so that doing as you suggest will almost certainly result in nonsense P values. So I suggest you seek local statistical help