You are given the following set of data:

y x1 x2 x3 33 9 192 40 44 11 397 47 34 10 235 37 60 13 345 61 20 11 245 23 30 7 235 35 y x1 x2 x3 45 12 296 52 25 9 235 27 53 10 295 57 45 13 335 50 37 11 243 41 44 13 413 51

a. Determine the appropriate correlation matrix and use it to predict which variable will enter in the first step of a stepwise regression model.

b. Use standard stepwise regression to construct a model, entering all significant variables.

c. Construct a full regression model. What are the differences in the model? Which model explains the most variation in the dependent variable?