Question 1: Scraps of iron were selected based on their densities, xi, and their iron contents, yi, were measured. The results were as follows: 2.8 2.9 3 3.1 3.2 3.2 3.2 3.3 3.4 Yi 27 23 30 28 30 32 34 33 30 (a) Find the regression line of y on x. (10 P) (b) Plot the scatter diagram of the data pair and regression line. (10 P) (c) Find the R2 values. (5 P) (You need to do research on this question.)