Use the data below to answer this questions.
a.) Generate a scatter of the data
b. ) Report the monthly averages (January for all years, February for all years etc.)
c.) Is there seasonality? Is there a trend?
d.) How can you forecast the value for March 2020? Generate that forecast.
e.) (Not technical) This forecast will for sure be wrong. Why?
Reference period | Employment 3 |
Persons | |
Jan-01 | 1,879.50 |
Feb-01 | 1,901.00 |
Mar-01 | 1,925.30 |
Apr-01 | 1,914.60 |
May-01 | 1,961.50 |
Jun-01 | 1,960.60 |
Jul-01 | 1,953.40 |
Aug-01 | 1,940.20 |
Sep-01 | 1,928.00 |
Oct-01 | 1,909.20 |
Nov-01 | 1,896.40 |
Dec-01 | 1,881.40 |
Jan-02 | 1,880.20 |
Feb-02 | 1,884.00 |
Mar-02 | 1,902.60 |
Apr-02 | 1,913.40 |
May-02 | 1,937.40 |
Jun-02 | 1,990.90 |
Jul-02 | 1,994.80 |
Aug-02 | 2,013.10 |
Sep-02 | 2,002.30 |
Oct-02 | 1,982.50 |
Nov-02 | 1,969.00 |
Dec-02 | 1,959.20 |
Jan-03 | 1,928.20 |
Feb-03 | 1,952.40 |
Mar-03 | 1,980.40 |
Apr-03 | 1,972.00 |
May-03 | 1,987.80 |
Jun-03 | 2,018.70 |
Jul-03 | 2,027.80 |
Aug-03 | 2,030.20 |
Sep-03 | 2,012.20 |
Oct-03 | 2,032.30 |
Nov-03 | 2,008.30 |
Dec-03 | 2,026.80 |
Jan-04 | 1,982.30 |
Feb-04 | 1,967.20 |
Mar-04 | 1,981.60 |
Apr-04 | 1,977.40 |
May-04 | 2,020.50 |
Jun-04 | 2,074.90 |
Jul-04 | 2,069.50 |
Aug-04 | 2,064.10 |
Sep-04 | 2,050.80 |
Oct-04 | 2,057.30 |
Nov-04 | 2,037.30 |
Dec-04 | 2,056.50 |
Jan-05 | 2,017.60 |
Feb-05 | 2,030.60 |
Mar-05 | 2,039.10 |
Apr-05 | 2,051.70 |
May-05 | 2,097.70 |
Jun-05 | 2,115.90 |
Answers:
Answer a)
Months |
Persons |
Jan-01 |
1,879.50 |
Feb-01 |
1,901.00 |
Mar-01 |
1,925.30 |
Apr-01 |
1,914.60 |
May-01 |
1,961.50 |
Jun-01 |
1,960.60 |
Jul-01 |
1,953.40 |
Aug-01 |
1,940.20 |
Sep-01 |
1,928.00 |
Oct-01 |
1,909.20 |
Nov-01 |
1,896.40 |
Dec-01 |
1,881.40 |
Jan-02 |
1,880.20 |
Feb-02 |
1,884.00 |
Mar-02 |
1,902.60 |
Apr-02 |
1,913.40 |
May-02 |
1,937.40 |
Jun-02 |
1,990.90 |
Jul-02 |
1,994.80 |
Aug-02 |
2,013.10 |
Sep-02 |
2,002.30 |
Oct-02 |
1,982.50 |
Nov-02 |
1,969.00 |
Dec-02 |
1,959.20 |
Jan-03 |
1,928.20 |
Feb-03 |
1,952.40 |
Mar-03 |
1,980.40 |
Apr-03 |
1,972.00 |
May-03 |
1,987.80 |
Jun-03 |
2,018.70 |
Jul-03 |
2,027.80 |
Aug-03 |
2,030.20 |
Sep-03 |
2,012.20 |
Oct-03 |
2,032.30 |
Nov-03 |
2,008.30 |
Dec-03 |
2,026.80 |
Jan-04 |
1,982.30 |
Feb-04 |
1,967.20 |
Mar-04 |
1,981.60 |
Apr-04 |
1,977.40 |
May-04 |
2,020.50 |
Jun-04 |
2,074.90 |
Jul-04 |
2,069.50 |
Aug-04 |
2,064.10 |
Sep-04 |
2,050.80 |
Oct-04 |
2,057.30 |
Nov-04 |
2,037.30 |
Dec-04 |
2,056.50 |
Jan-05 |
2,017.60 |
Feb-05 |
2,030.60 |
Mar-05 |
2,039.10 |
Apr-05 |
2,051.70 |
May-05 |
2,097.70 |
Jun-05 |
2,115.90 |
Scatter of the data is as under:
Answer b)
The monthly averages (January for all years, February for all years etc.):
Month |
Persons |
Month |
Persons |
Month |
Persons (Monthly Average) |
Jan-01 |
1,879.50 |
Jan-02 |
1,880.20 |
Jan-03 |
1,879.85 |
Feb-01 |
1,901.00 |
Feb-02 |
1,884.00 |
Feb-03 |
1,892.50 |
Mar-01 |
1,925.30 |
Mar-02 |
1,902.60 |
Mar-03 |
1,913.95 |
Apr-01 |
1,914.60 |
Apr-02 |
1,913.40 |
Apr-03 |
1,914.00 |
May-01 |
1,961.50 |
May-02 |
1,937.40 |
May-03 |
1,949.45 |
Jun-01 |
1,960.60 |
Jun-02 |
1,990.90 |
Jun-03 |
1,975.75 |
Jul-01 |
1,953.40 |
Jul-02 |
1,994.80 |
Jul-03 |
1,974.10 |
Aug-01 |
1,940.20 |
Aug-02 |
2,013.10 |
Aug-03 |
1,976.65 |
Sep-01 |
1,928.00 |
Sep-02 |
2,002.30 |
Sep-03 |
1,965.15 |
Oct-01 |
1,909.20 |
Oct-02 |
1,982.50 |
Oct-03 |
1,945.85 |
Nov-01 |
1,896.40 |
Nov-02 |
1,969.00 |
Nov-03 |
1,932.70 |
Dec-01 |
1,881.40 |
Dec-02 |
1,959.20 |
Dec-03 |
1,920.30 |
Third year monthly average = (Month Year 01 + Month Year 02) / 2
Answer c)
There is both seasonality and trend:
As can be seen, there is cyclic changes in the monthly numbers so it is seasonal.
Also there is a trend increase from year 1 to year 2 (denoted by the straight line) so there is a trend.
Answer d)
Calculation of forecast the value for March 2020.
Yearly total for Year 2001 and Year 2002 is as under:
Year |
Yearly total |
Year-01 |
23051.1 |
Year-02 |
23429.4 |
Linear trend line for this forecast is :
y = 378.3x + 22673
“x” is the number of year (for year 2020, x=20)
Based on the linear trend line formula, the forecast till year 2020 is as under:
Year |
Yearly total |
Year-01 |
23051.1 |
Year-02 |
23429.4 |
Year-03 |
23807.9 |
Year-04 |
24186.2 |
Year-05 |
24564.5 |
Year-06 |
24942.8 |
Year-07 |
25321.1 |
Year-08 |
25699.4 |
Year-09 |
26077.7 |
Year-10 |
26456 |
Year-11 |
26834.3 |
Year-12 |
27212.6 |
Year-13 |
27590.9 |
Year-14 |
27969.2 |
Year-15 |
28347.5 |
Year-16 |
28725.8 |
Year-17 |
29104.1 |
Year-18 |
29482.4 |
Year-19 |
29860.7 |
Year-20 |
30239 |
Seasonal factor of the forecast is as under: