The given data follows a graph that is a approximately a U, this form is call a parabola and it models a quadratic function.
As the graph is a parabola it has a vertex, a point where the graph is divided into a decreasing part and an increasing part, the vertex in the given data is at year 3 before that year the function decrease and after that year the function increase. Then, after year number 3 the number of pieces sold will increase each year.
Based of the graph the store owner should continue stocking this particular brand of jeans
