Quantitative and Qualitative Forecasting

7

l-ott r,r: r.s rt tl chupter I I 459

Computing a Seasonal Factor from thc Actual Data and Trend l,inc

e)frceI Fo the Excl tffiplate, visit

-mhhe.@m4@bs14e.

700

300

Qu.*ren

I II F_- 201 1

IiI

FtoM T[sNn AcruaL Eeue'rroN Arrrorntt FIT : 176.i + 52.31

R.qtro or' ACTUAL _ TREND

20t2-----------sr SBnsoN,u- Facror (Avsnact or S.q.Mn Qulnrens n Bor:sYrans)

2411

I

lt

lil

IV

2012

I

II

ilt

IV

300

2A0

220

530

520

420

400

700

280.6

332.9

385.1

/aa I

48S.6 qt1 a

594.2

1.19

0

I 1.25 110.79

ilt 0.70

iv 1.28

0.74

1.18

(2)

Deseasonalized Demand

(1)

Psntoo (/) QUARTER

(3) ACTLTAL

I)rrralNo (y)

(4)

AVERAGE op rnr S,tttE QUARTERS OF EACH YEAR

(s) (6) DESEASONALiZED

Sr.rsoN.a.r Dr.u.rNo (y',r) l- \( l uk Col . (1 , + CuL. (51

(7) (8) TXlt

1: CoL. (l ) x (CoL. ll' C0L. (6)

1 I 600 (600 + 2,400 + 3,800)/3 . = ?,266.r

2 ll 1,550 (.1 ,550 + 3,100 + 4,500)/3 : 3.050

lll 1,500 (1,500 + 2,600 + 4 000)13 0.97 : 2,740

4 tv 1 ,s00 (1,500 + 2,900 + 4 900)/3 1.12: 3,1 00

0.82

1.10

0.82

1.10 0.97 1.12

0.82 1.10

0.97

1ZO3

735.7

1,412.4

1,544.0

1,344.8

2,942.4 ) R)47 2,676.2 2AOOO

4,659.2 4,100.4 +, lt/.J /?o)o

333"r0J.

/J3./

2,824.7

4,631.9

5,379.0

14,713.2

16,948.4 18,733.6

20,798.9

41,932.7

41 ,004.1 45,290.1

52,114.5 265.706.9

16

5l 6 ll 7 llt 8tv 9l

10 ll 11 lll 12 IV 7B

2 4AO

3,100 2,600 2,900

3,800 4,500 4,000 4,900

33,350. s_

; 78 _ ^ , ^ Ztyo- nry" t65.706.9 - t?r6.5)2.779.2 _ .4' )r - = o.r " .i _ ---- 659 _ij(.

o+z.z 1t

Ya:3335A/p:2]792 a: t:- bt - 2.719.2 - 342.2(6.5): 554.9 Thereforc, Y - a i bl- 554,9 1 342.2t

36 49 64

B1

100

121

144

650

.Column 3 and column 6 totals should be equal at 33,350. Differences are due to rounding. Column 5 was rounded to two decimal places.

exhibit 18.10

400

_s00

200

100