Time series analysisis for bussiness and com

Time series analysisis for bussiness and com

1. Previous Year Questions

2. Q. A time series is a set of observations taken at: A) Random points of time B) Fixed intervals of time C) Unequal intervals of time D) None of the above B) Fixed intervals of time

3. Q. The variable that changes with time in a time series is called: A) Independent variable B) Dependent variable C) Control variable D) Constant B) Dependent variable

4. Q. Seasonal variations repeat themselves after: A) 2 years B) 1 year C) 6 months D) Randomly B) 1 year

5. B Least Square Which method fits a straight line through data points? A) Moving average B) Least squares C) Ratio to trend D) Semi-average

6. The least squares trend equation is of the form: A) Y = a + bX B) Y = abX C) Y = aX + b D) Y = a/ bX

7. Q. The graphical method of trend estimation is: A) Accurate B) Subjective C) Complex D) Based on formulas B) Subjective

8. Q. In a linear trend equation , ‘ b ’ represents: A) Average value B) Rate of change C) Constant D) Intercept B) Rate of change  

9. Q.The ratio-to-trend method is used to measure: A) Trend B) Seasonal variation C) Cyclical variation D) Irregular variation B) Seasonal variation

10. Q. The average value of all seasonal indices is always: A) 100 B) 50 C) 0 D) 10 A) 100

11. Q. The cyclical variation represents: A) Random fluctuation B) Business cycle C) Long-term trend D) Seasonal pattern B) Business cycle

12. Q. In additive model, when all variations are removed, we get: A) Constant value B) Trend only C) Zero D) Seasonally adjusted value A) Constant value

13. Q. Exponential smoothing is mainly used to: A) Detect irregularities B) Smooth short-term fluctuations C) Estimate cyclical movement D) Eliminate seasonality B) Smooth short-term fluctuations

14. Q. Time series analysis helps in: A) Quality control B) Decision making C) Sampling D) Hypothesis testing B) Decision making

15. Q. Which of these is not a use of time series analysis? A) Forecasting B) Studying relationships between variables C) Understanding trends D) Planning B) Studying relationships between variables

16. Q. In the least square trend , the value of ‘ a ’ represents: A) Slope B) Intercept C) Rate of change D) Time interval B) Intercept  

17. Q. The ratio-to-trend method needs the estimation of: A) Moving average B) Trend line C) Seasonal index D) Irregular factor B) Trend line

18. Q. Time series analysis assumes that: A) Future is independent of past B) Future follows past patterns C) Randomness dominates D) Past data are useless B) Future follows past patterns

19. Q. The difference between additive and multiplicative models is based on: A) Type of data B) Nature of relationship between components C) Time interval D) Forecasting method B) Nature of relationship between components

20. Given Σ Y=150, Σ X=0, Σ XY=60, Σ X²=20, n=5 → b = ? A) 2 B) 3 C) 4 D) 1 Hint: b = Σ XY/ Σ X²

21. Q. Given data: 10, 14, 18, 22, 26. Find the 3‑year moving average centered at the third observation. Answer: 18 Solution: MA = (14 + 18 + 22)/3 = 54/3 = 18.

22. Q. Series: 100, 110, 120, 130, 140. Using centered X = −2, −1, 0, 1, 2 compute b for least‑squares trend. Answer: 10.0 Solution: Σ X² = 4 + 1 + 0 + 1 + 4 = 10. Σ XY = (−2×100) + (−1×110) + (0×120) + (1×130) + (2×140) = (−200 −110 +0 +130 +280) = 100. So b = Σ XY/ Σ X² = 100/10 = 10.

23. Q. Using ratio‑to‑trend: if original = 300 and trend = 250, seasonal index (%) = ? Answer: 120.0% Solution: SI = (Original / Trend) × 100 = 300/250 × 100 = 1.2 × 100 = 120.

24. Q: If trend value = 250 and seasonal index = 80, expected actual = ? Answer: 200 Solution: Actual = Trend × SI/100 = 250 × 0.8 = 200.