statistics
posted by karen .
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. Suppose a random sample of earthquakes gave the following information.
As x increases, does the value of r imply that y should tend to increase, decrease, or remain the same? Explain.
Since r is zero, as x increases, y decreases.
Since r is negative, as x increases, y remains the same.
Since r is negative, as x increases, y decreases.
Since r is positive, as x increases, y increases.
Since r is positive, as x increases, y remains the same.
I think it is D

Information missing, so I cannot help with the first part.
Positive correlation indicates that both variables increase and decrease together. A negative correlation indicates one variable increases while the other increases. Thus both the third and fourth choice are correct.