I have a sample size of 30 subjects, divided into three groups of 10 each. all the subjects have performed a repetition test, and each participant has a score out of 100. My main aim is to compare performance differences across the three groups using this final repetition score. To decide whether I should use parametric or non-parametric analysis, I need to check the normality of distribution of the score.
When I conducted shapiro-wilk test to test the distribution for each group, and I got(p>0.05) for all the groups. I also conducted a one-sample ks.test() for each group and the results were (p<0.01). I am confused, which one should I follow? which one of the results is more valid? taking into consideration my small sample size. below are the histograms and qqnorm plots of the three groups