如何知道随机森林生成的回归模型是否正确?(MSE和% Var(y))

I tried to use random forests for regression. The original data is a data frame of 218 rows and 9 columns. The first 8 columns are categorical values ( can be either A, B, C, or D), and the last column V9 has numerical values that can go from 10.2 to 999.87.I tried to use random forests for regression. T