PERAMALAN PRODUK IRAWAN 683-SP – PT. JWL
Irawan 682 Bulan
Demand
Januari
114.774
Februari
68.013
Maret
65.861
April
114.028
Mei
114.582
Juni
126.242
Juli
92.117
Agustus
78.888
September
101.747
Oktober
104.519
November
77.634
Desember
88.086
Total 1.146.490
Metode Peramalan Terpilih: •
Metode Kuadratis •
Metode Siklis
1. Metode Kuadratis
KUADRATIS t
y t²
t³ t
⁴ ty
t²y t
yt
1 114.774
1 1
1 114.774
114.774 13
89.274 2
68.013 4
8 16
136.026 272.052
14 93.664
3 65.861
9 27
81 197.584
592.751 15
97.079 4
114.028 16
64 256
456.110 1.824.440
16 99.519
5 114.582
25 125
625 572.910
2.864.550 17
100.984 6
126.242 36
216 1.296
757.449 4.544.694
18 101.473
7 92.117
49 343
2.401 644.816
4.513.709 19
100.987 8
78.888 64
512 4.096
631.104 5.048.832
20 99.526
9 101.747
81 729
6.561 915.725
8.241.527 21
97.089 10
104.519 100 1.000
10.000 1.045.193
10.451.925 22
93.677 11
77.634 121 1.331
14.641 853.969
9.393.654 23
89.290 12
88.086 144 1.728
20.736 1.057.035
12.684.420 24
83.928
78 1.146.490 650 6.084
60.710 7.382.694
60.547.328 222
42.286
Universitas Sumatera Utara
� = �� �
2
�
2
− � � �
4
� = 650
2
− 12 × 60.710 = −306.020 � = � � � � − � � ��
� = 78 ×
1.146.490
− 12 ×
7.382.694
= 833.898 � = � �
2
� � − � � �
2
� � = 650 ×
1.146.490
− 12 ×
60.547.328
= 18.650.570 � = � � � �
2
− � � �
3
� = 78 × 650 − 12 × 6.084 = −22.308 � = �� ��
2
− � � �
2
� = 78
2
− 12 × 650 = −1.716 � =
�� − �� �� − �
2
= 5.853,246 � =
� − �� �
= −487,630
� = ∑ � − � ∑ � − � ∑ �
2
� = 83.908,066
�
′
= � + �� + ��
2
�
′
= 83.908,066 + 5.853,246 + −487,630�
2
�
′
= 83.908,066 + 5.853,2461 + −487,6301
2
=
89.273,68
≈
89.274
���� =
∑ |
��
�
|
� �=1
�
=
2,22 12
= 18,50
2. Metode Siklis
Jumlah periode adalah: � =
12 2
= 6
Universitas Sumatera Utara
SIKLIS t
Y Sin2πtn Cos2πtn
Sin 2πtnCos
2πtn Sin2
2πtn Cos2
2πtn YSin2πtn YCos2πtn
1
114774 0,866
0,500 0,433
0,750 0,250
99394,28 57387
2 68013
0,866 -0,500
-0,433 0,750
0,250 58899,26
-34006,5
3 65861,25
0,000 -1,000
0,000 0,000
1,000 0,00
-65861,25
4 114027,5
-0,866 -0,500
0,433 0,750
0,250 -98747,82
-57013,75
5
114582 -0,866
0,500 -0,433
0,750 0,250
-99228,01 57291
6 126241,5
0,000 1,000
0,000 0,000
1,000 0,00
126241,5
7 92116,5
0,866 0,500
0,433 0,750
0,250 79772,89
46058,25
8 78888
0,866 -0,500
-0,433 0,750
0,250 68317,01
-39444
9
101747,25 0,000
-1,000 0,000
0,000 1,000
0,00 -101747,25
10 104519,25 -0,866
-0,500 0,433
0,750 0,250
-90513,67 -52259,625
11 77633,5
-0,866 0,500
-0,433 0,750
0,250 -67230,61
38816,75
12 88086,25
0,000 1,000
0,000 0,000
1,000 0,00
88086,25
78 1.146.490
6 6
-49.336,665 63.548,375
∑ y = t a + b
∑ sin�
2 πt
n
� + c ∑ cos�
2 πt
n
� 1.146.490
= 12 a + b 0 + c 0 a
=
1.146 .490 12
a = 95.540,833
∑ y sin�
2 πt
n
� =a
∑ sin�
2 πt
n
� + b ∑ sin
2
�
2 πt
n
�+ c ∑ sin�
2 πt
n
�cos�
2 πt
n
� -49.336,665
= 95.540,833 0 + b 6 + c 0 b
=
−49.336,665 6
b = -8.222,778
∑ y cos �
2 πt
n
� = a
∑ cos �
2 πt
n
�+ c ∑ cos
2
�
2 πt
n
�+ b ∑ sin�
2 πt
n
�cos�
2 πt
n
� 63.548,375
= 95.540,833 0 + c 6 + -8.222,778 0 c
=
63.548 ,375 6
c = 10.591,395
y’= a + b sin �
2 πt
n
�+ c�
2 πt
n
� y’= 95.540,833 – 8.222,778 sin
�
2 πt
n
� +5509,416 cos �
2 πt
n
� y’= 95.540,833 – 8.222,778 sin
0,866 + 5509,416 cos 0,500 = 93.715,605
Universitas Sumatera Utara
���� =
∑ |
��
�
|
� �=1
�
=
1,96 12
= 16,32
Metode Terpilih: Siklis
Verifikasi Peramalan
y yt
e=y-yt |MR|
UCL LCL
114.774 93.716
21.058 -
49.378,57 -49.378,57
68.013 83.124
-15.111 36.169,60
49.378,57 -49.378,57
65.861
84.949
-19.088 3.976,98
49.378,57 -49.378,57
114.028
97.366
16.661 35.749,63
49.378,57 -49.378,57
114.582 107.957
6.625 10.036,90
49.378,57 -49.378,57
126.242 106.132
20.109 13.484,73
49.378,57 -49.378,57
92.117
93.716
-1.599 21.708,38
49.378,57 -49.378,57
78.888
83.124
-4.236 2.637,10
49.378,57 -49.378,57
101.747 84.949
16.798 21.034,02
49.378,57 -49.378,57
104.519 97.366
7.153 9.644,62
49.378,57 -49.378,57
77.634
107.957
-30.324 37.477,15
49.378,57 -49.378,57
88.086
106.132
-18.046 12.277,98
49.378,57 -49.378,57
204.197,08
PERAMALAN PRODUK IRAWAN 684-S – PT. JWL
-100.000 -50.000
50.000 100.000
P T
. JW
L
Peramalan Irawan 683-SP tahun 2016
Irawan 683-SP UCL
LCL
Universitas Sumatera Utara
Irawan 682 Bulan
Demand
Januari
80.786
Februari
58.149
Maret
124.014
April
76.981
Mei
96.601
Juni
137.403
Juli
113.036
Agustus
142.224
September
111.110
Oktober
115.477
November
145.007
Desember
68.058
Total 1.268.844
Metode Peramalan Terpilih: •
Metode Eksponensial •