我没明白chart 1

问题如下：

Identify the regression assumption that may be violated based on Chart 1, RETvs. VIX.

选项：

A.Independence of errors B.Independence of independent variables C.Linearity between dependent variable and explanatory variables

解释：

C is correct. Chart 1 is a scatterplot of RET versus VIX. Linearity between the dependent variable and the independent variables is an assumption underlying multiple linear regression. As shown in the following Revised Chart 1, the relationship appears to be more curved (i.e., quadratic) than linear.