(2 points) The least squares method requires that the variance σ2σϵ2 of the error variable ϵ is a constant no matter what the value of x is. When this requirement is violated, the condition is called: A. homoscedasticity B. non-independence of ϵ C. heteroscedasticity D. influential observation In regression analysis, the coefficient of determination R2R2 measures the amount of variation in y that is: A. caused by variation in x B. unexplained by variation in x C. explained by variation in x D. both A and B are correct answers Help Entering Answers