Question

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.

x	3.4	4.3	3.3	4.5	2.6	3.2	3.4
y	4.5	9.5	11.2	10.0	7.9	3.9	5.5

(a) Make a scatter diagram of the data.

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Line

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Vertical Parabola

Horizontal Parabola

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WebAssign Graphing Tool

Graph LayersToggle Open/Closed

• After you add an object to the graph you can use Graph Layers to view and edit its properties.

Then visualize the line you think best fits the data.

(b) Use a calculator to verify that Σx = 24.7, Σx² = 89.75, Σy = 52.5, Σy² = 443.81 and Σxy = 189.83.

Compute r. (Round to 3 decimal places.)


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

Given our value of r, y should tend to decrease as x increases.Given our value of r, y should tend to increase as x increases.     Given our value of r, y should tend to remain constant as x increases.Given our value of r, we can not draw any conclusions for the behavior of y as x increases.

Answer 1

a) scatter plot

so this shows a line

b) correlation coefficient