This problem refers to the pond ecology data of Chapter 5, Problem 20.
a. Determine the squared multiple correlation for the regression of copepod count on zooplankton and phytoplankton counts.
b. Determine the partial correlation between each independent variable in (a) and copepod count, controlling for the other independent variable. Using the technique of Problem 2, perform tests of significance of the partial correlations.
c. Based on your answers in (b), which independent variables should be included in the regression model, and in what order of importance?