Estimating repair and replacement costs of water pipes. Refer to the IHS Journal of Hydraulic Engineering (September 2012) study of water pipes susceptible to breakage, Exercises 11.21 (p. 658) and 11.37 (p. 666). Recall that civil engineers used simple linear regression to model the ratio of repair to replacement cost of commercial pipe (y) as a function of the diameter (x, in millimeters) of the pipe. The Minitab printout of the analysis is reproduced below. Are the engineers able to conclude (at a = .05) that the cost ratio increases linearly with pipe diameter? If so, provide a 95% confidence interval for the increase in cost ratio for every 1-millimeter increase in pipe diameter.