# Kruskal-Wallis or Friedman

I have 3 groups of 30 fish.

group 1: without anaesthesia
group 2: clove oil anaesthesia
group 3: MS-222 anaesthesia


Every group was investigated at six levels of time (0, 0.5, 1, 2, 6 and 24 hours after anaesthesia). The data aren't normal. Which test to use? Kruskal-Wallis or Friedman?

• What is your exact research question? Do you want to check all 6 levels of time or only the final level with respect to initial level? What exactly are you testing? Is the outcome variable a numeric one or categorical / ordered? Add more details to your question. – rnso Apr 12 '15 at 7:32
• I want to compare all 6 levels of time in within and between groups. In fact, I want to compare the effects of different methods of anesthesia on the number of the specific cells. – Sara Apr 13 '15 at 13:20
• Graphical methods may be the best for this. If you post some sample data here, it will be helpful. – rnso Apr 13 '15 at 14:44