Repair and replacement costs of water pipes. Refer to the IHS Journal of Hydraulic Engineering (September 2012) study of water pipes, Exercise 11.21 (p. 658). Refer, again, MATHSAT NW H2OPIPE x 5 10 15 x

a. y 10 5 15 5 10 15 x

b. y

c. 10 5 15 5 10 15 x to the Minitab simple linear regression printout (p. 659) relating y = the ratio of repair to replacement cost of commercial pipe to x = the diameter (in millimeters) of the pipe.

a. Locate the value of s on the printout.

b. Give a practical interpretation of s.