What can we learn from Upper R squared , the coefficient of determination? Question content area bottom Part 1 A. Upper R squared is the hypothesis that a data set in a regression analysis follows the simpler of two proposed linear models that are nested within each other. B. Upper R squared tests whether the slope of a regression line differs significantly from 0. C. Upper R squared is a goodness-of-fit test. It tells us the percentage of variation in cost that is associated with changes in the cost driver. D. Upper R squared refers to whether the estimated cost function makes economic sense