re a relationship between the amount of dust carried over large areas of the Atlantic and the Caribbean and the amount of rainfall in African regions?...

African droughts and dust          Is there a relationship between the amount of dust carried over large areas of the Atlantic and the Caribbean and the amount of rainfall in African regions? In an article (by J.M. Prospero and P.J. Lamb, Science, vol. 302, 2003, pp.1024-1027) the following scatterplots were given along with corresponding regression equations and correlations. The precipitation index is a measure of rainfall.

               a. Match the following regression equations and correlations with the appropriate graph.

                               (i) y=14.05-7.18x;            r=-0.75

                               (ii) y=16.00-2.36x;           r=-0.44

                               (iii) y=12.80-9.77x;          r=-0.87

b. Based on the scatterplots and information in part a, what would you conclude about the relationship between dust amount and rainfall amounts?