In the First-Order Model $E ( y ) = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } + \beta _ { 3 } x _ { 3 } , \beta _ { 2 }$

True/False

In the first-order model $E ( y ) = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } + \beta _ { 3 } x _ { 3 } , \beta _ { 2 }$ represents the slope of the line relating $y$ to $x _ { 2 }$ when $\beta _ { 1 }$ and $\beta _ { 3 }$ are both held fixed.