Question 1. Briefly define what data science is (one sentence), and name two aspects of data science. [2 marks] Question 2. Explain briefly the difference between interval and ratio data. [2 marks] Question 3. Briefly explain what "data dimension reduction" means in data pre-processing. Why is it important? [2 marks] Question 4. Both Mean and Median are typical ways to explore the data's statistical summary using "average. List two ways to explore the "spread" of data. [2 marks] Question 5. Briefly explain the overfitting issue in classification. [2 marks]