It is necessary for me to write about the 2.5th and 97.5th percentiles of a data set. What is the correct way of writing this?
This post talks about "zeroth", "n-th" and even "epsilonth" as generalisations of the -th suffix, but I haven't found any guidelines for non-integers.
I feel that 2.5th percentile sounds better than 2.5-percentile. Do you agree?