15.41 Global warming. Return to the global warming data in Exercise 15.14.
(a) Verify the equation given for the least-squares line in that exercise.
(b) Suppose you were told only that the average global temperature was 14.25 degrees Celsius. You now want to “predict” the year in which this occurred. Find the equation of the least-squares regression line that is appropriate for this purpose. What is your prediction?
(c) The two lines in parts (a) and (b) are different. Explain clearly why there are two different regression lines.