CDO

i have a confusion regarding the trend using cdo prompt >cdo trend infile.nc ofile1.ncofile2.nc< for a gridded file of e.g. wind vector at 850 and 200 mb levels in my case. I want to get trend at 200 and 850mb levels for july and august
i need some help regarding this command as i want to get trend for winds for july and aug months seperately.

I need to understand since we get 2 outputs, which one is valid and what is the statistical significance of this trend using CDO.
Sharing the file with mean values for july and august wind vector is not possble as they exceed the limit unfortunately.

Regards
Rizwan Katim