124
b
=
n
?
xy -
?
x
?
y n
?
x
2
-
(
?
x)
2
b
=
36(3.430.195,00) - (666)(188.588)
36(16.206) - (666)
2
b
=
-15,11
a
=
y
-
b
x
a
= 5238,5556 - (-15,11).(18,50)
a
= 5518,00
Trend (T) = a + bx = 5518,00 - (15,11 * 7) = 5412,26
Ft = Trend * Adjusted Index = 5412,26 * 0,97 = 5263,66
•
Periode ke – 8
Seasonal :
12 Month Moving Total = Demand2 + Demand3 + ….. + Demand
13
=
5198
+
6175
+
6813
+
4867
+
5228
+
5159
+
5275 + 5213 + 6267 + 4605 + 5005 + 5221
= 65.026 ,00
2
Year
Moving
Total
=
12
Month
Moving
total
x
+
12
Month
Moving
Total
x+1
= 65.026,00 + 64.826,00 = 129.852,00
Centered =
2YearMovingTotalx
=
129.852,00
=
5410,50
Seasonalindex =
24
Demandx
Centeredx
24
=
5275
=
0,97
5410,50
Adjusted Index = 1,01 (diperoleh dari perhitungan index)
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