1. Data Penjualan
UD.
ROTI KUKUS
DATA
PENJUALAN ROTI KUKUS
BULAN
|
Y
|
X
|
XY
|
X²
|
X⁴
|
X²Y
|
JANUARI
|
1545
|
-9
|
-13905
|
81
|
6561
|
125145
|
FEBRUARI
|
1560
|
-7
|
-10920
|
49
|
2401
|
76440
|
MARET
|
1442
|
-5
|
-7210
|
25
|
625
|
36050
|
APRIL
|
1248
|
-3
|
-3744
|
9
|
81
|
11232
|
MEI
|
1664
|
-1
|
-1664
|
1
|
1
|
1664
|
JUNI
|
1212
|
1
|
1212
|
1
|
1
|
1212
|
JULI
|
1144
|
3
|
3432
|
9
|
81
|
10296
|
AGUSTUS
|
1872
|
5
|
9360
|
25
|
625
|
46800
|
SEPTEMBER
|
1751
|
7
|
12257
|
49
|
2401
|
85799
|
OKTOBER
|
1768
|
9
|
15912
|
81
|
6561
|
143208
|
∑
|
15206
|
0
|
4730
|
330
|
19338
|
537846
|
n
= 10, dengan syarat ∑x = 0
Persamaan
Trend GarisLengkung
Y
= a + bx + c (x)2
a. Mencari nilai
a dan c
∑y = n . a + c . ∑x2
∑x2y = ∑x2. a + c . ∑x4
 |
||
15206 = 10 . a + c .
330 ........... (x
33) = 501798 = 330 . a + c . 10890
537846 = 330 . a + c . 19338..... (x 1) = 537846
= 330 . a + c . 19338 -
-36048/-8448 = c
4, 27 = c
15206
= 10 . a + c . 330
15206
= 10 . a + 4,27 . 330
15206
= 10a + 1409,1
15206
– 1409,1 = 10a
13796,9
= 10a
13796,9 / 10 =a
1379,69 = a
b. Mencari nilai b
b = ∑xy / ∑x2
= 4730 / 330
= 14,33
2. Ramalan penjualan untuk bulan
November 2016 – April 2017
November 2016: Y = a +
bx + c (x)2
= 1379,69 + 14,33 . 11 + 4,27 (11)2
=
1379,69 + 157,63 + 516,67
= 2053,99 = 2054
Desember2016 : Y = a + bx + c (x)2
= 1379,69 + 14,33 . 13 + 4,27 (13)2
= 1379,69 + 186,29 + 721,63
= 2287,61 = 2288
Januari2107
: Y
= a + bx + c (x)2
= 1379,69 + 14,33 . 15 + 4,27 (15)2
=
1379,69 + 214,95 + 960,75
= 2555,39 = 2555
Februari2017 : Y = a + bx + c (x)2
= 1379,69 + 14,33 . 17 + 4,27 (17)2
= 1379,69 + 243,61 + 1234,03
= 2857,33 = 2857
Maret2107 : Y
= a + bx + c (x)2
= 1379,69 + 14,33 . 19 + 4,27 (19)2
= 1379 ,69 + 272,27 + 1541,47
= 3193,43 = 3193
April 2017 : Y
= a + bx + c (x)2
= 1379,69 + 14,33 . 21 + 4,27 (21)2
= 1379,69 +
300,93 + 1883,07
= 3563,69 = 3564
3. Grafik
Trend GarisLengkung
