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Question: Repair and replacement costs of water pipes.Pipes used in a water distribution network are susceptible to breakage due to a variety of factors. When pipes break, engineers must decide whether to repair or replace the broken pipe.

A team of civil engineers estimated the ratio of repair to replacement cost of commercial pipe based on the diameter (in millimeters) of the pipe. (IHS Journal of Hydraulic Engineering,September 2012.) Data for a sample of 13 different pipe sizes are provided in the table. Use a scatterplot to aid the engineers in detecting a trend in the data. Does it appear that the ratio of repair to replacement cost is strongly associated with pipe size?

DIAMETER	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

Step by step solution

01

Constructing the scatterplot

The graph is given below:

02

Determining the trend and the association between the data

There is a positive trend in the data set. It means that the ratio of repair to replacement cost is positively related to the size of the pipe. As the size of the pipe goes on increasing, the ratio of repair to replacement cost also increases.

Therefore, yes, there is a strong association between the ratio of repair to replacement and the size of the pipe.

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