Given Sxx=∑(xi−xˉ)2=50S_{xx} = \sum (x_i - \bar{x})^2 = 50Sxx=∑(xi−xˉ)2=50, Syy=∑(yi−yˉ)2=200S_{yy} = \sum (y_i - \bar{y})^2 = 200Syy=∑(yi−yˉ)2=200, and Sxy=∑(xi−xˉ)(yi−yˉ)=80S_{xy} = \sum (x_i - \bar{x})(y_i - \bar{y}) = 80Sxy=∑(xi−xˉ)(yi−yˉ)=80, what is the coefficient of determination R2R^2R2?
0.640.640.64
0.400.400.40
0.800.800.80
0.320.320.32