# What test should I use if:

I'm trying not to have a seizure among the bunch of numbers and data I have. My experiment data consists of three non-equal, non-parametric groups, and I need to compare those groups to state if there exists statistical difference between those groups. Which will be the best test I can use to achieve so? Group 1 data: n=12, mean=0.886, SD=0.74 | Group 2 data: n=16, mean= 0.554, SD= 0.39 | Group 3 data: n=13, mean= 0.79, SD= 0.68

• Do you have all your data, or just the summaries you listed here? Commented Jan 30, 2016 at 23:01
• I have all of my data if you need it Commented Jan 30, 2016 at 23:17
• I don't need the data; I was just making sure that you had it available and weren't solely relying on the summary statistics for your analysis. Commented Jan 30, 2016 at 23:18
• Could you explain what a "non-parametric group" is and what you mean by a "statistical difference"?
– whuber
Commented Jan 30, 2016 at 23:19
• Data are neither parametric nor nonparametric; those are adjectives that apply to models or techniques. If you mean "not normally distributed" that's not at all the same thing as "nonparametric" and similarly "parametric" is not at all the same thing as "normally distributed" -- one can fit parametric non-normal models and correspondingly, one can happily use nonparametric procedures on data drawn from normal distributions. Please amend your post to more clearly express the actual situation. Commented Jan 30, 2016 at 23:23