In a regression analysis involving 30 observations, the following estimated regression equation was obtained. y = 18.9 + 3.6x1 - 2.5x2 + 7.7X3 + 2.9x4 (a) Interpret b, in this estimated regression equation. O b, = 7.7 is an estimate of the change in y corresponding to a 1 unit change in X3 when x1, X2, and x are held constant. O b, = 3.6 is an estimate of the change in y corresponding to a 1 unit change in x, when x, , x3, and x are held constant. O b, = -2.5 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x3, and x are held constant. O b, = 2.9 is an estimate of the change in y corresponding to a 1 unit change in x when x, , x2, and x3 are held constant. O b, = 3.6 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, X3, and x are held constant. Interpret b, in this estimated regression equation. O b, = 3.6 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x,, and x are held constant. O b, = 7.7 is an estimate of the change in y corresponding to a 1 unit change in X? when x,, x2, and x are held constant. O b, = 2.9 is an estimate of the change in y corresponding to a 1 unit change in x when x1, x2, and x3 are held constant. O b, = -2.5 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x3, and x are held constant. O b, = -2.5 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x,, and x, are held constant. Interpret b, in this estimated regression equation. O b2 = 7.7 is an estimate of the change in y corresponding to a 1 unit change in x, when x1, X3, and x are held constant. O b2 = -2.9 is an estimate of the change in y corresponding to a 1 unit change in x when x,, x,, and x? are held constant. O b, = -2.5 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x3, and x are held constant. O b3 = 3.6 is an estimate of the change in y corresponding to a 1 unit change in x3 when x, , x2, and x are held constant. O ba = 7.7 is an estimate of the change in y corresponding to a 1 unit change in x? when x,, x,, and x are held constant. Interpret by in this estimated regression equation. O b = 3.6 is an estimate of the change in y corresponding to a 1 unit change in x when x , x,, and x, are held constant. O ba = 2.9 is an estimate of the change in y corresponding to a 1 unit change in x when x1, X2, and x3 are held constant. O b. = 7.7 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, x3, and x, are held constant. O b. = -2.5 is an estimate of the change in y corresponding to a 1 unit change in x, when x,, X3, and x are held constant. O ba = 2.9 is an estimate of the change in y corresponding to a 1 unit change in x3 when x1, X2, and x are held constant. (b) Predict y when x1 = 10, x2 = 5, X3 = 1, and x4 = 2