Question

If Linear regression model perfectly first i.e., train error is zero, then _____________________

(a) Test error is also always zero

(b) Test error is non zero

(c) Couldn’t comment on Test error

(d) Test error is equal to Train error

I had been asked this question in an internship interview.

I'm obligated to ask this question of Linear Regression topic in chapter Commands, Packages, Visualizing Data and Linear Regression of R Programming

Answer 1

Correct answer is (c) Couldn’t comment on Test error

To explain I would say: Test Error depends on the test data. If the Test data is an exact representation of train data then test error is always zero. But this may not be the case.