Discussion 3

In the following multiple-choice questions, please circle the correct answer.

1.A time series is:

  1. a set of measurements on a variable collected at the same time or approximately the same period of time.
  2. a set of measurements on a variable taken over some time period in sequential order
  3. a model that attempts to analyze the relationship between a dependent variable and one or more independent variables
  4. a model that attempts to forecast the future value of a variable

2.The time series component that reflects a long-term, relatively smooth pattern or direction exhibited by a time series over a long time period (more than one year) is called:

  1. trend
  2. cyclical
  3. seasonal
  4. random variation

3.The time series component that reflects variability over short repetitive time periods and has duration of less than one year is called:

  1. trend
  2. cyclical
  3. seasonal
  4. random variation

4.The time series component that reflects the irregular changes in a time series that are not caused by any other component, and tends to hide the existence of the other more predictable components, is called:

  1. trend
  2. cyclical
  3. seasonal
  4. random variation

5.The time series component that reflects a wavelike pattern describing a long-term trend that is generally apparent over a number of years is called:

  1. trend
  2. cyclical
  3. seasonal
  4. random variation

6.The term “seasonal variation” may refer to:

  1. the four traditional seasons
  2. systematic patterns that occur during the period of one week
  3. systematic patterns that occur over the course of one day
  4. All of the above are correct statements

7.Which of the four time series components is more likely to exhibit the relative steady growth of the population of Egypt from 1970 to 2000?

  1. Trend
  2. Cyclical
  3. Seasonal
  4. Random variation

8. The following linear trend equation was developed for annual sales from 1995 to 2001 with 1995 the base or year one. = 500 + 60t (in $ thousands). What are the estimated sales for 2004 (in $ thousands)?

A) $ 500

B) $ 560

C) $1,040

D) $1,100

9. The following linear trend equation was developed for the annual sales of the Jordan Manufacturing Company. = 500 + 60t (in $ thousands). How much are sales increasing by?

A) $ 60,000 per year

B) $ 6,000 per month

C) $ 500,000 per year

D) $ 6,000 per year

10. If the least squares equation for sales data going from 2000 to 2004 is = 10 + 1.3t (in $ millions), what is the value of t and the forecast for 2006?

A) t = 6, y = 17.8

B) t = 0, y = 10.0

C) t = 7, y = 19.1

D) t = 10, y = 0.0

11. What is the formula for "a" in the least squares trend equation using the coded method?

A)

B)

C)

D) X times Y

12. If the exports (in $ millions) for the period 2000 through 2004 were $878, $892, $864, $870 and $912 respectively, what are these values called?

A) Moving average

B) Linear trend equation

C) Logarithmic trend equation

D) Time series data

13. In the linear trend equation which variable represents the average change in the dependent variable for every unit change in time?

A) a

B) b

C) t

D)

14. For a time series beginning with 1988 and extending up to 2007, which year would be coded with a one when using the coded method?

A) 1986

B) 1988

C) 1989

D) 1998

15.We calculate the three-period centered moving averages for a time series for all time periods except the:

  1. first period
  2. last period
  3. first and last period
  4. first and last two periods

16.We calculate the five-period centered moving average for a time series for all time periods except the:

  1. first five periods
  2. last five periods
  3. first and last period
  4. first two and last two periods

17.The number of four-period centered moving averages of a time series with 20 time periods is:

  1. 28
  2. 24
  3. 20
  4. 16

18.The following trend line was calculated from quarterly data for 1994 – 1998.

where t = 1 for the first quarter of 1994. The trend value for the second quarter of the year 1999 is:

  1. 0.705
  2. 0.820
  3. 0.815
  4. 0.810

19.The following are the values of a time series for the first four time periods:

t / 1 / 2 / 3 / 4
/ 23 / 25 / 28 / 24

Using a four-period moving average, the forecasted value for time period 5 is:

  1. 25.3
  2. 25.7
  3. 25
  4. 26

20.The following linear trend was estimated using a time series with 25 time periods:

The forecasted value for time period 26 is:

  1. 180.8
  2. 178.3
  3. 175.8
  4. Not enough information is given to answer the question

21.Suppose that we calculate the centered four-period moving average of the following time series

t / 1 / 2 / 3 / 4 / 5 / 6
/ 16 / 28 / 21 / 15 / 26 / 12

The centered moving average for period 3 is:

  1. 22.5
  2. 21.25
  3. 20.50
  4. 18.5

22.Weekly toy sales (in $1,000s) in a department store for the past three months are shown below.

Month / Week / Sales
1 / 1 / 14
2 / 22
3 / 20
4 / 16
2 / 1 / 18
2 / 20
3 / 24
4 / 20
3 / 1 / 22
2 / 26
3 / 24
4 / 18

Compute the four-week centered moving averages.