Your question is Explain the purpose of a validation set. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
What is the purpose of a validation set, and is it necessary?
Asked in the Phone screen stage. ML fundamentals after project discussion.
Explain how you would use a validation set in an ML workflow, when it is essential, and when alternatives like cross-validation or a held-out test set may be enough. Keep the answer grounded in how you would prevent overfitting, choose hyperparameters, and avoid training-serving skew.