Which of the Following Statements Are True?
A) in General $\beta _ { α }$

Multiple Choice

Which of the following statements are true?

A) In general, it is not only permissible for some independent or predictor variables to the mathematical functions of others, but also of often highly desirable in the sense that the resulting model may be much more successful in explaining variation in y than any model without such predictors.
B) Polynomial regression is indeed a specific case of multiple regression.
C) The coefficient $\beta _ { α }$

In the multiple regression model $Y = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } + \cdots \cdot + + \beta _ { α } x _ { α } + \varepsilon$

Is interpreted as the expected change in Y with a 1-unit increase in $x _ {k }$

, when $x _ { 1 } , x _ { 2 } , \ldots , x _ { k-1}$
Are held fixed.
D) All of the above statements are true.
E) None of the above statements are true.