A quadratic model is a mathematical model represented by a quadratic equation, which is a polynomial of degree two in one or more variables. A quadratic function is a function of degree two, and its graph is a parabola. The general form of a quadratic function is f(x) = ax^2 + bx + c, where a, b, and c are real numbers and a ≠ 0. The relationship between two variables can be modeled by a quadratic equation such as Y = aX^2 + bX + c, or by a system of quadratic equations. A quadratic model is useful for inferring relationships from data, especially when bivariate data tends to rise and fall or vice versa. The quadratic model is often used to model real-life situations, such as monthly precipitation or the height of a basketball over time.