Is the magnitude of an earthquake related to the depth below the surface at which the quake occurs? Let x be the magnitude of an earthquake (on the Richter scale), and let y be the depth (in kilometers) of the quake below the surface at the epicenter. The following is based on information taken from the National Earthquake Information Service of the U.S. Geological Survey. Additional data may be found by visiting the website for the service.

X	2.9	4.2	3.3	4.5	2.6	3.2	3.4
y	5.0	10.0	11.2	10.0	7.9	3.9	5.5

a. Would you say the correlation is low, moderate, or strong? positive or negative?

b. Verify that x = 24.1, x² = 85.75, , y = 53.5, y² =458.31, and xy = 190.18.

c. Compute r.

d. As x increases, does the value of r imply that y should tend to increase or decrease? Explain