Linear Equation Algebra Review 17 Data for length of the tail (in millimeters) and age (in days) of tadpoles is entered into a statistics software package and results in a regression equation of y = 15 - 1.5x. What is the correct interpretation of the slope if the length of the tail is the response variable and the age is the explanatory variable? The length of the tail increases by 1.5 millimeters, on average, when the tadpole's age increases by 1 day. The length of the tail decreases by 1.5 millimeters, on average, when the tadpole's age increases by 1 day. The length of the tail increases by 15 millimeters, on average, when the tadpole's age increases by 1 day. The length of the tail decreases by 15 millimeters, on average, when the tadpole's age increases by 1 day