The Galapagos Islands off the coast of Ecuador provide an excellent laboratory for studying factors that influence the development and survival of different species. The data below give the number of species of plants and related geographic variables for 30 different islands. Counts are given both for the total number of species, and the number of species that occur only on that specific island (the endemics). The variables from left to right are as follows.
On close inspection of the data, you will notice that the number of species and endemics on the island of Daphne Minor was not recorded (the periods denote missing observations). Build a simple linear regression model to predict the number of species (S) on Daphne Minor based on the single best geographic variable A1, El, D1, D2, or A2, indicating your reason for the choice of variable. (Ignore the endemics in this question.) Specifically: