Streams and hard water. In a study of streams in the Adirondack Mountains, the following relationship was found between the water's pH and its hardness (measured in grains):
![1889_a6a22bf8-d11d-4167-8305-a65a4fb63a53.png](https://secure.tutorsglobe.com/CMSImages/1889_a6a22bf8-d11d-4167-8305-a65a4fb63a53.png)
a) Is it appropriate to summarize the strength of association with a correlation? Explain.
b) Would Kendall's tau be an appropriate measure? Explain.