I have ratio scale data for 3 related samples. What is the statistical test that I can use to check whether there's any significant difference between the 3 groups? (I tried Friedman, but I'm doubtful whether it can be used for ratio scale data.)
This cite says Friedman test can be used for continuous scale data as well, but I need to make sure about it as this is the only place I found that fact. In every other place, it speaks about ratio scale data.
NOTE: I collected data from 15 people. i.e. sample size is 15. The same 15 people faced the 3 different situations where we need to compare