4. [-/5.31 Points] DETAILS BBUNDERSTAT12 9.1.016.S. MY NOTES ASK YOUR TEACHER 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. 3.4 4.1 3.3 45 2.6 3.2 3.4 5.4 9.7 11.2 10.0 7.9 3.9 5.5 LA USE SALT (a) Make a scatter diagram of the data. Then visualize the line you think best fits the data. 11 4.5 4.5 4.0 4.0 y (depth (in kilometers)) y (depth (in kilometers)) y (depth (in kilometers)) 3.5 y (depth (in kilometers) 3.5 3.0 3.0 25 25 3.0 3.5 4.0 45 3.0 3.5 4.0 4.5 5 6 7 8 9 10 11 5 6 9 10 11 x (magnitude of an earthquake x (magnitude of an earthquake x (magnitude of an earthquake x (magnitude of an earthquake (on the Richter scale)) (on the Richter scale)) (on the Richter scale)) (on the Richter scale)) (b) Use a calculator to verify that Ex = 24.5, Ex = 88.07, Ey = 53.6, Ey = 456.56 and Exy = 191.81. Computer. (Round your answer to four 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 remain constant as x increases. Given our value of r, y should tend to increase as x increases. Given our value of r, we can not draw any conclusions for the behavior of y as x increases. 5. [-/5.31 Points] DETAILS BBUNDERSTAT12 9.2.005.MI. MY NOTES ASK YOUR TEACHER We use the form y = a + bx for the least-squares line. In some computer printouts, the least-squares equation is not given directly. Instead, the value of the constant a is given, and the coefficient b of the explanatory or predictor variable is displayed. Sometimes a is referred to as the constant, and sometimes as the intercept. Data from a report showed the following relationship between elevation (in thousands of feet) and average number of frost-free days per year in a state