7.Analysis of neural networks: a random matrix approach 3.Underfitting and overfitting Underfitting Just right! overfitting Solution: Solution: 1.add new feature 1.adjust model parameter 2.increase feature dimension by cross-validation 3.use non-liner model 2.regularization 4.use boosting method 3.increase training data 55 7. Analysis of neural networks: a random matrix approach 3.Underfitting and overfitting Solution: 1. add new feature 2. increase feature dimension 3. use non-liner model 4. use boosting method Solution: 1. adjust model parameter by cross-validation 2. regularization 3. increase training data