So, here’s the Bayes error if for instance we have 10 variables with mean 0.5 in a class and -0.5 in the other class:
Bayes_error=1-pnorm(1*sqrt(10*0.5^2));

If we had more complicated things, like 5 variables with mean 0.5,0.6,0.7,0.8,0.9 in a class and -0.5,-0.6,-0.7,-0.8,-0.9 in the other, we could do something like:
mus=c(0.5,0.6,0.7,0.8,0.9);
Bayes_error=1-pnorm(1*sqrt(t(mus)%*%mus));
or not vectorized: Bayes_error=1-pnorm(1*sqrt(sum(mus*mus)));

Usually when I have such a simple question, I just type it into Google Scroogle and voilà. You know, standard Tech support cheat sheet algorithm. But this time it just didn’t work. Oddly enough, that basic question doesn’t seem to be answered anywhere. Or at least not clearly.
Anyway, after searching a bit around the PubMed search limits, I eventually found the Core clinical journals subset. And those core clinical journals, aka Abridged Index Medicus (AIM) are just it: the “main” (“most important”) PubMed journals. Check out the list: Nature, Lancet, The New England journal of medicine, etc.
So, to search among those titles only you can go to limits and select the Core clinical journals subset, or more simply you can just add jsubsetaim within your PubMed query.

If you don’t, your statistical skills require an emergency treatment (unless you actually don’t use statistics) because you are likely to draw erroneous excessive conclusions.
If you do, well, I can’t conclude.

Also, note that automatically installing additional packages should work fine on this portable version (I did so with my previous 2.10.0 portable, so no reason it wouldn’t work with that one).