EMC Proven Professional – Data Science and Big Data Analytics — Question 36

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?

Answer options

• 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)

Correct answer: A

Explanation

The correct answer is A because it indicates that the second differences of the time series are constant, which is a hallmark of a quadratic trend. Options B and C suggest linear or percentage changes, which do not reflect the nature of a quadratic trend, while option D does not clearly indicate a consistent second difference.