To begin, thank you for your answers.   @ballardw : I used kruskal-Wallis one-way analysis with Dunn's post-tests and i presented the data with median and IQR in the paper. The reviewers asked me to describe data with median differences and 95%CI between groups. He said :"generally  it is not helpful to refer to a "statistical difference". As a reader i would like to see the magnitude of the difference and the confidence intervals that should be applied to it" I would like to calculate this median differences and adjusted for multiple comparisons. There are 8 treatments groups so i had to realise 28 multiples comparisons. The treatment variable is categorical   I tested the @Rick_SAS's method, i did proc quantreg and i used the estimate statment but i don't know what test i have to use for multiple comparisons, Sidak?   I read in papers that authors used bootstrap approach, is it a better approach?   Thanks ... View more