A quadratic trend equation y_t = 900 + 80t - 5t² was fitted to a company's sales. This result implies that the sales trend:

Question

Quizplus · Accepted Answer

The quadratic equation is in the form of y = a + bt + ct^2, where a, b, and c are constants. The vertex of the parabola is at t = -b/2c. In this case, b = 80 and c = -5, so the vertex is at t = -80/(2*(-5)) = 8. This means that the sales trend hit a peak in period 8.

A Quadratic Trend Equation Yt = 900 + 80t -

A Quadratic Trend Equation Y_t = 900 + 80t -