Appropriate test


New Member
I have one group (n=21). And on this group i determine efficiency level(%) with the use of 3 different model specifications. So for every unit i have 3 results of efficiency. I am interested which statistics test should i use to determine if there is difference if i use different model on the same unit. There is no normal distribution of results and sample is small. I would like to find evidence that is not matter which model i use i get the same efficiency result. Thank you.


Active Member
Hi Nyx,

If you use different models, I assume there must be a difference between the models, so with small sample size, you may not have enough power to prove it, but with a big sample size it will be always significance ...on the other hand, you may calculate the effect size and show that the effect size - the difference between the averages (like cohen's d) is very small.

You may just use a confidence interval for each model and show it in one chart, if the models are similar it will be very clear.