Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 25

Geology: Earthquakes 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 Richer scale), and ley 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 Brase/Brase statistics site at www.cengagebrain.com and finding the link to earthquakes.

a) Make a Scatter diagram and draw the line you think best fits the data.
(b) Would you say the correlation is low, moderate, or strong positive or negative
(c) Use a calculator to verify that x = 24.1, x 2 = 85.75, y = 53.5, y 2 = 458.31, and xy = 190.18, Computer r. As x increases, does the value of r imply that y should tend to increase or decrease Explain.