I'm using Random Forests to determine the importance of numerous environmental predictor variables for predicting forest structural variables. One of the response variables only contains 5 unique values, and so this warning message is produced:
Warning messages: 1: In randomForest.default(m, y, ...) : The response has five or fewer unique values. Are you sure you want to do regression?
My data is legitimate regression data, so can I ignore this warning? Is it still ok to perform regression when there are limited response values?