An economist wants to predict the Gini of the US by Year. Select the answer choice that correctly interprets R-Squared. Group of answer choices 0.451751 is the proportion of variability of Gini Coefficient unexplained by our least squares line. 0.451751 is the proportion of variability of Years explained by our least squares line. 0.451751 is the proportion of variability of Gini Coefficient explained by our least squares lines 0.451751 is the proportion of variability of Years unexplained by our least squares line.