TIME SERIES BASED FORECASTING

TIME SERIES BASED FORECASTING

Year

Sales

Moving averages

Centered moving average

Seasonal Irregular Value

Seasonal Index

Seasonally Adjusted Sales

2007

Quarter 1

16

16

Quarter 2

21

15.750

15.875

1.323

1.281

16.395

Quarter 3

9

15.500

15.625

0.576

0.623

14.443

Quarter 4

18

15.750

15.625

1.152

1.108

16.249

2008

Quarter 1

15

15.750

15.750

0.952

0.918

16.336

Quarter 2

20

16.250

16.000

1.250

1.281

15.613

Quarter 3

10

17.250

16.750

0.597

0.623

16.051

Quarter 4

18

18.000

17.625

1.021

1.108

16.245

2009

Quarter 1

17

19.000

18.500

0.919

0.918

18.519

Quarter 2

24

19.000

19.000

1.263

1.281

18.735

Quarter 3

13

19.250

19.125

0.680

0.623

20.867

Quarter 4

22

18.750

19.000

1.158

1.108

19.856

2010

Quarter 1

17

18.500

18.625

0.913

0.918

18.519

Quarter 2

25

18.750

18.625

1.342

1.281

19.516

Quarter 3

11

19.000

18.875

0.583

0.623

17.657

Quarter 4

21

19.750

19.375

1.084

1.108

18.953

2011

Quarter 1

18

20.750

20.250

0.889

0.918

19.608

Quarter 2

26

21.667

21.208

1.226

1.281

20.297

Quarter 3

14

19.500

20.583

0.680

0.623

22.472

Quarter 4

25

25.000

22.250

1.124

1.108

22.563

Seasonally adjusted sales figure as a percentage of the predicted value

Year

Time period

Predicted Sales (PS)

Seasonally Adjusted Sales (SAS)

SAS/PS*100

Quarter 1

1

2007

Quarter 2

2

15.528

16.395

105.583

Quarter 3

3

15.882

14.443

90.939

Quarter 4

4

16.236

16.249

100.080

Quarter 1

5

16.59

16.336

98.468

2008

Quarter 2

6

16.944

15.613

92.144

Quarter 3

7

17.298

16.051

92.791

Quarter 4

8

17.652

16.245

92.029

Quarter 1

9

18.006

18.519

102.849

2009

Quarter 2

10

18.36

18.735

102.042

Quarter 3

11

18.714

20.867

111.504

Quarter 4

12

19.068

19.856

104.132

Quarter 1

13

19.422

18.519

95.350

2010

Quarter 2

14

19.776

19.516

98.685

Quarter 3

15

20.13

17.657

87.714

Quarter 4

16

20.484

18.953

92.525

Quarter 1

17

20.838

19.608

94.097

2011

Quarter 2

18

21.192

20.297

95.776

Quarter 3

19

21.546

22.472

104.297

Quarter 4

20

21.9

22.563

103.027

Comments on the cyclical variation around the trend line

The linear predicted trend line shows significant trend values because the cyclical variation shows that there is a very minor difference that could ...