Predict the value of y when x1 = 20, x2 = 20, and x3 = 30.

Exercises 11–15 refer to the following data set:

x1 *2 x3 69.8 7.9 37.3 62.4 32.3 9.3 20.2 40.7 66.9 13.3 30.5 48.7 87.5 27.4 38.8 35.8 93.5 9.3 40.1 28.9 65.1 23.3 29.2 46.9 50.4 58.2 26.3 24.1 11.5 48.7 21.5 19.0 52.8 25.5 32.2 34.7 58.0 8.3 37.9 23.7 65.6 30.1 34.6 56.2 42.3 21.1 23.9 42.6