• Choosing the correct parameters whether is underfitting or overfitting

• Much harder evaluate hypothesis if we have much more features

• Split training examples, for first the usual training set.
• The second, is the test set.
• 70% for training set and 30% set for test set for the split term
• Recommended for the training set to be shuffled, or random sorted

• Inject the theta from J theta training set and implement it for theta in Jerror test
• These are the test error for linear regression
• How about logistic regression at classification?