Fig. 3

Relationship between Lambda and Mean Squared Error. The Y axis represents the mean squared error (MSE). The X axis represents values of lambda. The figure shows that as the strength of the penalty increases, MSE decreases to a point and then increases. The lambda value associated with the lowest MSE on the test data was 0.03. This point represents the lambda value at which model performance on the test data was best. The model was then refit using all data and this optimal value of lambda