Statistical indices to evaluate the regression framework. Multiple evaluation indicators (MSE, RMSE, MAE, R2, and PCC) were computed for a comprehensive and accurate assessment of the regression framework. The MSE was used to calculate the deviation between the predicted and true values. The RMSE was the square root of the MSE result. The two indicators show the accuracy of the model prediction. The R2 was used to assess the goodness-of-fit of the regression framework. The r was used to assess the correlation between two variables in the regression framework. The indicators were calculated using the open-source tools scikit-learn and the scipy library.