Concept explainers
Repair and replacement costs of water pipes. Refer to the IHS Journal of Hydraulic Engineering (September 2012) study of water pipes, Exercise 11.12 (p. 622). Recall that a team of civil engineers used
Diameter (mm) | Ratio | |
80 | 6.58 | |
100 | 6.97 | |
125 | 7.39 | |
150 | 7.61 | |
200 | 7.78 | |
250 | 7.92 | |
300 | 8.20 | |
350 | 8.42 | |
400 | 8.60 | |
450 | 8.97 | |
500 | 9.31 | |
600 | 9.47 | |
700 | 9.72 | |
Source.· eased on ISH Journal or Hydraulic Engineering, Volume 18, Issue 3, pp 241-251. Copyright September 2012 |
a. Find the least squares line relating ratio of repair to replacement cost (y) to pipe diameter (x) on the printout.
b. Locate the value of SSE on the printout. Is there another line with an average error of 0 that has a smaller SSE than the line, part a? Explain.
c. Interpret, practically, the values
d. Use the regression line to predict the ratio of repair to replacement cost of pipe with a diameter of 800 millimeters.
e. Comment on the reliabilrty of the prediction, part d.
Minitab Output for Exercise 11 .21
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Statistics for Business and Economics (13th Edition)
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