As part of a study at a large university, data were collected on n = 224 freshmen computer science (CS) majors in a particular year. The researchers were interested in modeling y, a student's grade point average (GPA) after three semesters, as a function of the following independent variables (recorded at the time the students enrolled in the university):
x ₁ = average high school grade in mathematics (HSM)

x ₂ = average high school grade in science (HSS)

x ₃ = average high school grade in English (HSE)

x ₄ = SAT mathematics score (SATM)

x ₅ = SAT verbal score (SAW)

A first-order model was fit to data with R ² = 0.211.

What is the correct interpretation of R ² , the coefficient of determination for the model?

• We are 79% confident that the model is useful for predicting y.
• Approximately 79% of the sample variation in GPAs can be explained by the first-order model.
• We expect to predict GPA to within approximately .21 of its true value.
• Approximately 21 % of the sample variation in GPAs can be explained by the first-order model.