06-14-2017 08:22 PM
I'm using the operator "Correlation Matrix" on rapidminer, which I believe uses Pearson Correlation, and the operator is able to calculate correlations for every variable type, including binominals (dichotomous) and polinominals.
I would like to know: how exactly is the operator calculating the correlation for example between a binominal and a numerical attribute? Wouldn't a pearson correlation only allow numerical variables? Does it simply convert binominals to 0 and 1, or is it doing something else?
Thanks in advance,
Solved! Go to Solution.
06-14-2017 09:44 PM
06-15-2017 02:24 AM
RapidMiner uses internally a mapping to integers for all nominal types. This mapping is used for the corellation. It's somewhat statistical not too good. That's why we throw a problem if you do it.