4. Monthly total production costs and the number of units produced at a local company over a period of 10 months are shown in the data set Production Cost. a) Use a simple linear regression model to develop an estimated regression equation to best describes the relationship between X and Y b) Construct a standardized residual plot. Based upon the standardized residual plot, does a simple linear regression model appear to be appropriate? c) Develop a second-order model and find out the standardized residual plot. d) Do you prefer the estimated regression equation developed in part (a) or part (c)? Explain which one is a better fit.