On analyzing your time series data you suspect that the data represented as y1, y2, y3, … , yn-1, yn may have a trend component that is quadratic in nature. Which pattern of data will indicate that the trend in the time series data is quadratic in nature?

A.
(y3-y2) � (y2-y1) = ���= (yn-yn-1)-(yn-1-yn-2)

B.
(y2-y1) = (y3-y2) = ��. = (yn-yn-1)

C.
((y2-y1) /y1 ) * 100% = ��.((yn-yn-1)/yn-1) * 100%

D.
(y4-y2) � (y3-y1) = ���= (yn-yn-2)-(yn-1-yn-3)