Let’s say, a “Linear regression” model perfectly fits the training data (train error is zero). Now, Which of the following statement is true?
A. You will always have test error zero
B. You can not have test error zero
C. None of the above
Solution: C
Test error may be zero if there no noise in test data. In other words, it will be zero, if the test data is perfect representative of train data but not always.