Refer to the compressive strength data in Exercise 11-3. Use the summary statistics provided to calculate R² and provide a practical interpretation of this quantity.

Exercise 11-3

An article in Concrete Research [“Near Surface Characteristics of Concrete: Intrinsic Permeability” (1989, Vol. 41)] presented data on compressive strength x and intrinsic permeability y of various concrete mixes and cures. Summary quantities are n = 14,Σy_i = 572, Σy_i² = 23,530,Σx_i = 43,  Σ x_i2 = 157.42, and Σx_iy_i = 1697.80. Assume that the two variables are related according to the simple linear regression model.