23:16 Nov 6, 2011 

17:38 Nov 6, 2011 

in the sense that a statement like 'a percent CV of less than 2%' is clumsy; it is much more common to say 'a CV of less than 2%'.

Apart from that, I find it a bit unusual to repeat an answer that was already given by somebody else, as happened here. If you want to add something to somebody else's answer, you can post a discussion entry or a reference entry.

16:54 Nov 6, 2011 

Maybe a study can't, but (the results) of a test can.

15:59 Nov 6, 2011 

Whichever answer is chosen, "a percentage change (or whatever) of 2 percent" is clumsy.
Also, we don't have enough context - "coeficiente de variación porcentual del ensayo" doesn't make sense. A study can't change by 2%.