In a simple linear regression y^=β0+β1x\hat{y} = \beta_0 + \beta_1 xy^=β0+β1x, what is the value of ∑i=1n(yi−y^i)xi\sum_{i=1}^{n} (y_i - \hat{y}_i)x_i∑i=1n(yi−y^i)xi?
000
xˉ\bar{x}xˉ
β1\beta_1β1
111