(a) Suppose you want to fit a second-order polynomial model to the data. Write the equations for least square regression in vectorfrnatrix form. Define all the variables in your equation and specify the dimensions of each. Write down the matrix of independent variable values, X. Hint: a second order polynomial model can2 be written 2as f= +x12+x+x+xllz+ +1.. .+x+xx+.. ..+xx 84 912 1434 (b) Make what you think is an appropriate analysis of the data to obtain your best model for radial run-out, y : i. Describe your approach and steps of analysis. ii. Report your model expression, the overall goodness-of-fit (e.g. ANOVA, esp. quuare and Adjusted quuare), estimated parameters, and their significance results (t-ratio or p-value). Hint: use stepwise least square regression. The terms included in the final model should be either a signicant variable or part ofa signicant variable. (c) Based on your final model, make a two-dimensronal contour plot of versus x1 and x3 A