I have a n=12 sample (and a matched-sample of 12)... I was planning on using t-tests, but now reconsidering it. Would it be correct to use a mann-whitney test to compare the means of the 2 samples (because of the sample size)?

I did K-S test to check for normality and no-significance was noted- so I'm assuming my data distributions are normal... was this the correct way to check for normal distribution. I tried looking at histograms to eye-ball it, but I don't get it!!

all things equal, are there disadvantages to using Mann-Whitney U rather than t-tests?

I'm trying to figure out the most appropriate way to analyze my data... any advice would be appreciated. Thanks.