I'd like to know if it makes sense to use Spearman's correlation on my dataset. Below are plots between my 3 variables :
Correlation plot (Spearman):
It seems it's pretty good but since I'm not from statistics I'm not sure. What do you think about it ?
Best Answer
In general, Spearman checks for monotonicity, and so it can be used for discrete variables. Also, at least by eye, your top pair-plot does seem to indicate monotone decrease.
The problem, though, is that Spearman works by ranks, and so has a problem with ties. Your data seems to have many ties in the 5 values it obtains. In this case, you might want to use the Kendall tau-b test, which addresses this problem.