What makes r  -1? Consider the data:

x  1 3 5 7 9 y  17 11 10 -1 -7

a. Sketch a scatterplot.

b. If one pair of (x, y) values is removed, the correlation for the remaining four pairs equals -1. Which pair has been removed?

c. If one y value is changed, the correlation for the five pairs equals -1. Identify the y value and how it must be changed for this to happen.