An article in concrete research ("near surface characteristics of concrete: intrinsic permeability," vol. 41, 1989), presented data on compressive strength x and intrinsic permeability y of various concrete mixes and cures. summary quantities are n=14, ∑yi=572, ∑yi2=23,530, ∑xi=43, ∑xi2=157.42, and ∑xiyi=1697.80. assume that the two variables are related according to the simple linear regression model.