In a regression analysis involving 30 observations, the following estimated regression equation was obtained. Interpret b 1, b 2, b 3, and b 4 in this estimated regression equation (to 1 decimal). Assume that for each coefficient statement, the remaining three variables are held constant. Enter negative values as negative numbers. b 1 = estimated change in y per 1 unit change in x 1 b 2 = estimated change in y per 1 unit change in x 2 b 3 = estimated change in y per 1 unit change in x 3 b 4 = estimated change in y per 1 unit change in x 4 Predict y when x 1 = 10, x 2 = 5, x 3 = 1, and x 4 = 2 (to 1 decimal).