Analisis Faktor-Faktor yang Memengaruhi Return Saham Perusahaan Sektor Industri Barang Konsumsi yang Terdaftar di Bursa Efek Indonesia

LAMPIRAN
LAMPIRAN 1
DATA RETURN, ROA, DER, EPS, PER, PBV PERUSAHAAN SEKTOR
INDUSTRI BARANG KONSUMSI YANG TERDAFTAR DI BURSA EFEK
INDONESIA PERIODE 2011-2015
KOD
TAHU RETUR
E
N
N
ROA
DER
EPS
PER
PBV
ADES
2011
(0,38)
8,22
1,51
44,02 22,94

4,74
2012
0,90
21,43
0,86
141,34 33,58
5,42
2013
0,04
12,62
0,67
94,35 21,20
4,46
2014
(0,31)
9,14
1,71
52,59 26,15
2,74
2015

(0,26)
10,03
0,99
55,67 18,23
1,82
RMB
2011
(0,01)
4,83
1,82
42,26 18,69
2,55
A
2012
(0,27) (4,66)
1,60
(44,66) (5,99)
2,18
2013
(0,02) (1,29)

1,47
(143,93) (4,60)
4,68
2014
(0,09) (1,23) (1,34)
(314,74) (5,45) (2,70)
2015
(0,02) (1,94) (1,02)
(226,32) (6,30) (1,17)
DVLA
2011
(0,02)
10,10
1,27
107,96 18,06
1,77
2012
0,47
13,86
0,28

132,95 22,71
2,25
2013
0,30
12,57
0,30
112,32 46,63
2,69
2014
(0,23)
6,55
1,28
72,26 23,39
1,97
2015
(0,23)
7,84
1,41
96,33 13,49
1,50

DLTA
2011
(0,07)
21,79
1,22
9.474,39 15,15
3,12
2012
1,29
28,64
0,25 13.327,84 44,31
6,83
2013
0,49
25,20
0,28 16.892,21 58,58
8,99
2014
0,03
12,04

0,30 17.989,77 37,50
8,17
2015
(0,99)
7,50
0,22
239,86 21,68
4,90
GGR
M
2011
0,55
12,68
0,59
2.576,86 48,80
4,86
2012
(0,09)
11,80
0,56

2.114,62 11,36
4,07
2013
(0,25)
12,63
0,73
2.278,45 25,30
2,75
2014
0,45
13,27
0,78
2.804,08 49,69
3,62
2015
(0,09)
19,16
0,67
3.353,71 24,11
2,78

HMSP
2011
0,39
41,72
0,88
1.839,93 27,70
0,59
2012
0,54
42,89
0,97
2.269,06 45,83
0,73
2013
0,04
44,48
0,94
2.468,28 33,30
0,62
2014

0,10
43,87
1,10
2.322,86 40,52
0,49
2015
0,37
42,26
0,19
2.227,36 36,26
0,66
INAF
2011
1,04
12,31
0,83
11,91 23,68
0,83

109


Universitas Sumatera Utara

ICBP

INDF

KLBF

KICI

KAEF

LMPI

TCID

MBTO

2012

2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012

1,02
(0,54)
1,32
(0,53)
0,11
0,50
0,31
0,28
0,03
(0,06)
0,27
0,13
0,02
(0,23)
0,05
(0,69)
0,18
0,46
(0,28)
(0,03)
0,50
0,00
(0,01)
(0,07)
1,14
1,18
(0,20)
1,48
(0,41)
(0,24)
0,24
(0,16)
(0,19)
(0,35)
0,07
0,43
0,08
0,47
(0,06)
0,00
(0,07)

19,57
(4,19)
9,09
10,43
13,57
14,86
13,51
14,16
15,01
39,13
38,06
24,02
40,99
28,04
18,41
19,85
15,41
17,07
16,02
8,41
12,38
17,55
14,86
(9,71)
19,57
18,91
6,58
8,56
7,82
9,79
8,29
(1,46)
6,22
8,50
12,38
13,92
14,92
19,41
26,15
9,88
11,47

0,83
1,19
1,11
1,59
0,42
0,48
0,60
0,66
0,62
0,70
0,74
0,81
1,08
1,13
0,27
0,28
0,33
0,27
0,25
0,36
0,43
0,33
0,23
1,43
0,43
0,44
0,68
0,75
0,74
0,68
0,99
1,07
1,04
0,98
0,11
0,15
0,24
0,44
0,21
0,35
0,40

13,68
(17,50)
0,38
2,12
354,38
391,42
383,31
434,18
501,32
557,11
544,33
389,12
586,11
422,47
149,96
202,17
42,04
45,25
43,90
2,59
16,37
53,76
34,08
(94,21)
309,26
370,48
38,83
46,42
45,55
5,38
2,32
(11,94)
1,73
3,93
696,48
747,88
796,49
866,95
2.707,93
39,87
42,54

24,13
(7,32)
37,61
18,50
14,67
19,93
26,61
30,17
26,88
13,64
14,42
16,96
21,52
12,25
22,67
21,18
29,74
40,44
20,07
18,64
26,49
23,62
17,20
(8,88)
35,33
24,46
15,20
31,56
19,10
18,10
25,09
(9,01)
16,52
24,21
21,06
24,71
24,94
20,21
18,79
17,81
12,44

1,57
0,80
1,86
0,88
2,83
3,79
4,48
5,08
4,79
1,28
1,50
1,53
1,44
1,05
5,30
1,26
6,89
8,74
5,66
0,49
0,56
0,50
0,47
0,47
0,55
0,59
2,19
4,73
2,59
0,51
0,63
0,55
0,45
0,48
1,52
2,02
2,02
2,75
1,93
1,10
0,94

110

Universitas Sumatera Utara

MYO
R

MERK

SCPI

MLBI

MRAT

ROTI

PSDN

2013
2014

(0,20)
(0,34)

5,64
3,47

0,36
0,37

15,11
2,73

2015

(0,30)

(3,00)

1,08

(13,14)

2011
2012
2013
2014
2015
2011
2012
2013
2014
2015

0,33
0,40
0,30
(0,20)
0,46
0,37
0,15
0,24
(0,15)
(0,96)

17,33
18,97
31,44
13,98
11,06
39,56
18,93
25,17
25,32
22,22

1,72
1,71
1,49
1,51
1,18
0,18
0,37
0,36
0,29
0,35

630,70
971,10
1.133,29
458,24
134,44
10.319,58
4.812,86
7.832,36
8.101,44
6.363,64

2011

(0,34)

(8,13)

1,47

(7.061,21)

2012

0,25

(2,81)

1,48

(3.435,19)

2013

(0,07)

(1,63)

1,83

2014
2015
2011
2012
2013
2014
2015
2011
2012

0,00
0,00
0,31
1,06
0,62
(0,99)
(0,31)
(0,23)
(0,02)

(4,74)
9,22
31,56
29,36
45,72
15,63
14,27
10,60
10,75

(1,04)
1,98
1,30
0,49
0,80
1,03
1,74
0,18
0,18

(3.379,90)
(17.350,39
)
38.700,47
24.080,78
21.518,98
55.587,52
377,26
212,11
65,11
71,85

2013
2014
2015
2011
2012
2013
2014
2015
2011
2012

(0,05)
(0,25)
(0,41)
0,25
1,08
(0,85)
0,36
(0,09)
5,20
(0,34)

(1,52)
9,48
5,21
25,27
28,38
6,67
6,80
10,00
9,66
8,75

1,16
0,30
0,32
0,39
0,81
1,30
1,23
1,28
1,04
0,67

(15,66)
17,22
2,44
114,52
147,33
31,22
37,26
53,45
16,57
17,79

20,19
16,56
(12,27
)

0,72
0,47

22,59
30,60
28,58
15,61
34,44
49,32
44,48
40,26
18,22
15,06
(10,78
)
(12,92
)
(10,54
)
(12,16
)
29,76
28,19
46,45
43,74
22,40
18,66
21,50
20,74
(13,70
)
20,32
39,53
29,03
46,83
32,67
37,18
23,67
18,71
21,52

4,51
5,00
5,97
4,56
5,25
6,01
8,17
8,27
6,47
0,52

0,34

4,17
6,51
0,55
(2,38)
1,03
0,56
0,47
0,60
0,47
0,54
0,60
0,54
0,53
0,39
0,24
6,16
0,48
6,56
7,30
5,39
2,16
0,72

111

Universitas Sumatera Utara

PYFA

SKLT

STTP

AISA

TSPC

ULTJ

UNVR

CEKA

2013

(0,27)

8,13

0,63

14,81

2014

(0,05)

(4,54)

1,64

(19,57)

2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011
2012
2013
2014
2015
2011

(0,15)
0,39
0,01
(0,17)
(0,08)
(0,17)
0,00
0,29
0,00
0,67
0,23
0,79
0,52
0,48
0,86
0,05
(0,31)
1,18
0,32
0,47
(0,42)
0,49
0,46
(0,13)
(0,12)
(0,39)
(0,11)
0,23
2,38
(0,17)
0,06
0,14
0,11
0,25
0,24
0,15
(0,14)

(6,87)
11,38
11,91
23,54
10,54
8,93
12,79
13,19
13,79
14,97
15,32
6,57
10,97
13,78
17,26
29,67
19,18
22,56
36,90
10,13
8,12
13,80
14,71
14,81
12,45
14,01
8,89
24,60
21,16
19,71
29,78
39,56
40,38
40,10
41,50
37,20
21,70

1,91
0,43
0,55
0,86
0,79
0,58
0,74
0,93
1,16
1,16
1,48
0,91
1,16
1,12
1,08
0,09
0,96
0,90
1,13
1,05
1,28
0,40
0,38
0,40
0,35
0,45
0,61
0,44
0,40
0,29
0,27
1,85
2,02
2,14
2,01
2,26
1,03

(29,60)
9,67
9,92
11,58
4,97
5,77
8,65
11,53
16,56
23,86
29,05
32,58
56,97
87,36
94,25
141,76
51,25
86,69
118,49
2,74
0,12
130,30
141,15
141,90
129,84
139,83
44,47
122,36
112,56
98,10
181,10
543,42
634,23
701,52
776,77
766,95
323,72

23,64
(17,20
)
(14,53
)
13,13
21,67
12,70
39,53
36,61
13,86
15,61
22,94
12,57
12,74
21,18
18,43
17,74
30,56
21,27
15,51
32,46
12,07
39,99
21,46
19,57
26,39
22,90
22,07
12,52
24,29
19,04
39,98
37,92
21,67
26,31
21,60
16,24
23,90
17,36
21,58

0,52
0,54
0,54
1,14
1,08
0,84
0,75
0,59
0,79
0,96
0,89
1,35
1,68
1,84
2,37
2,93
4,61
0,49
0,79
1,55
1,77
0,52
0,75
3,77
5,00
3,79
3,12
1,82
2,31
2,29
6,45
4,74
4,05
0,97
0,29
0,63
0,92
0,48
0,70

112

Universitas Sumatera Utara

2012
2013
2014
2015

0,37
(0,11)
0,29
(0,55)

15,68
16,08
13,19
17,17

1,22
1,02
1,39
1,32

196,12
218,72
137,82
179,07

42,98
14,90
18,14
21,74

0,83
0,65
0,83
0,63

113

Universitas Sumatera Utara

LAMPIRAN 2
HASIL PENGUJIAN MODEL DATA PANEL DENGAN COMMON
EFFECT MODEL (OLS)
Dependent Variable: RETURN?
Method: Pooled Least Squares
Date: 09/02/16 Time: 14:25
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?

-0.175864
0.003100
0.007956
-2.07E-06
0.011167
0.015132

0.131862
0.005160
0.088796
8.17E-06
0.004722
0.024223

-1.333700
0.600818
0.089599
-0.253278
2.364803
0.624716

0.1844
0.5489
0.9287
0.8004
0.0194
0.5331

R-squared
Adjusted R-squared
S.E. of regression
Sum squared resid
Log likelihood
F-statistic
Prob(F-statistic)

0.090362
0.058777
0.616990
54.81736
-137.3436
2.860951
0.017080

Mean dependent var
S.D. dependent var
Akaike info criterion
Schwarz criterion
Hannan-Quinn criter.
Durbin-Watson stat

0.154660
0.635963
1.911249
2.031674
1.960174
1.771721

114

Universitas Sumatera Utara

LAMPIRAN 3
HASIL PENGUJIAN MODEL DATA PANEL DENGAN FIXED
EFFECT MODEL (FEM)
Dependent Variable: RETURN?
Method: Pooled Least Squares
Date: 09/02/16 Time: 14:25
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?
Fixed Effects (Cross)
_ADES--C
_RMBA--C
_DVLA--C
_DLTA--C
_GGRM--C
_HMSP--C
_INAF--C
_ICBP--C
_INDF--C
_KLBF--C
_KICI--C
_KAEF--C
_LMPI--C
_TCID--C
_MBTO--C
_MYOR--C
_MERK--C
_SCPI--C
_MLBI--C
_MRAT--C
_ROTI--C
_PSDN--C
_PYFA--C
_SKLT--C
_STTP--C
_AISA--C
_TSPC--C
_ULTJ--C
_UNVR--C
_CEKA--C

-0.590524
0.022029
-0.153278
-1.73E-06
0.012042
0.113054

0.214889
0.009425
0.129330
1.05E-05
0.005323
0.039427

-2.748041
2.337355
-1.185170
-0.164694
2.262232
2.867403

0.0070
0.0212
0.2384
0.8695
0.0256
0.0049

-0.233450
0.489785
0.034663
-0.740602
-0.290785
-0.454549
0.649372
-0.149393
-0.338946
-0.756920
0.321903
0.507863
0.220345
-0.051238
0.152417
-0.214305
-1.064781
0.588551
-0.117938
0.048450
-0.439019
1.405576
-0.006207
0.371547
0.378349
0.159765
-0.237125
-0.121602
-0.120509
0.008785
Effects Specification

Cross-section fixed (dummy variables)

115

Universitas Sumatera Utara

R-squared
Adjusted R-squared
S.E. of regression
Sum squared resid
Log likelihood
F-statistic
Prob(F-statistic)

0.355807
0.165350
0.581010
38.82089
-111.4650
1.868175
0.007670

Mean dependent var
S.D. dependent var
Akaike info criterion
Schwarz criterion
Hannan-Quinn criter.
Durbin-Watson stat

0.154660
0.635963
1.952867
2.655349
2.238263
2.267490

116

Universitas Sumatera Utara

LAMPIRAN 4
HASIL PENGUJIAN MODEL DATA PANEL DENGAN RANDOM
EFFECT MODEL (REM)
Dependent Variable: RETURN?
Method: Pooled EGLS (Cross-section random effects)
Date: 09/02/16 Time: 14:27
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
Swamy and Arora estimator of component variances
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?
Random Effects (Cross)
_ADES--C
_RMBA--C
_DVLA--C
_DLTA--C
_GGRM--C
_HMSP--C
_INAF--C
_ICBP--C
_INDF--C
_KLBF--C
_KICI--C
_KAEF--C
_LMPI--C
_TCID--C
_MBTO--C
_MYOR--C
_MERK--C
_SCPI--C
_MLBI--C
_MRAT--C
_ROTI--C
_PSDN--C
_PYFA--C
_SKLT--C
_STTP--C
_AISA--C
_TSPC--C
_ULTJ--C
_UNVR--C
_CEKA--C

-0.178071
0.003202
0.006361
-2.03E-06
0.011195
0.015659

0.125085
0.004894
0.084060
7.73E-06
0.004462
0.022965

-1.423600
0.654314
0.075669
-0.262343
2.509108
0.681857

0.1567
0.5140
0.9398
0.7934
0.0132
0.4964

-0.004580
0.001973
-0.002519
-0.004729
-0.003768
-0.002132
0.008322
0.001034
-0.002402
-0.007248
0.001036
0.010316
-0.003663
0.001001
-0.003588
-0.000125
-0.009658
0.003440
-0.002323
-0.005463
-0.004233
0.021489
-0.003715
0.003863
0.008525
0.001519
-0.002068
0.004610
-0.000688
-0.004230
Effects Specification
S.D.

Rho

117

Universitas Sumatera Utara

Cross-section random
Idiosyncratic random

0.039428
0.581010

0.0046
0.9954

Weighted Statistics
R-squared
Adjusted R-squared
S.E. of regression
F-statistic
Prob(F-statistic)

0.091377
0.059828
0.615613
2.896326
0.015989

Mean dependent var
S.D. dependent var
Sum squared resid
Durbin-Watson stat

0.152910
0.634898
54.57306
1.777294

Unweighted Statistics
R-squared
Sum squared resid

0.090349
54.81818

Mean dependent var
Durbin-Watson stat

0.154660
1.769347

118

Universitas Sumatera Utara

LAMPIRAN 5
HASIL UJI CHOW
Redundant Fixed Effects Tests
Pool: Untitled
Test cross-section fixed effects
Effects Test

Statistic

Cross-section F
Cross-section Chi-square

d.f.

Prob.

1.634024
51.757246

(29,115)
29

0.0358
0.0058

Cross-section fixed effects test equation:
Dependent Variable: RETURN?
Method: Panel Least Squares
Date: 09/02/16 Time: 14:27
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?

-0.175864
0.003100
0.007956
-2.07E-06
0.011167
0.015132

0.131862
0.005160
0.088796
8.17E-06
0.004722
0.024223

-1.333700
0.600818
0.089599
-0.253278
2.364803
0.624716

0.1844
0.5489
0.9287
0.8004
0.0194
0.5331

R-squared
Adjusted R-squared
S.E. of regression
Sum squared resid
Log likelihood
F-statistic
Prob(F-statistic)

0.090362
0.058777
0.616990
54.81736
-137.3436
2.860951
0.017080

Mean dependent var
S.D. dependent var
Akaike info criterion
Schwarz criterion
Hannan-Quinn criter.
Durbin-Watson stat

0.154660
0.635963
1.911249
2.031674
1.960174
1.771721

119

Universitas Sumatera Utara

LAMPIRAN 6
HASIL UJI HAUSMAN
Correlated Random Effects - Hausman Test
Pool: Untitled
Test cross-section random effects
Chi-Sq.
Statistic

Chi-Sq. d.f.

Prob.

22.662997

5

0.0004

Random

Var(Diff.)

Prob.

0.003202
0.006361
-0.000002
0.011195
0.015659

0.000065
0.009660
0.000000
0.000008
0.001027

0.0194
0.1043
0.9671
0.7705
0.0024

Test Summary
Cross-section random

Cross-section random effects test comparisons:
Variable
ROA?
DER?
EPS?
PER?
PBV?

Fixed
0.022029
-0.153278
-0.000002
0.012042
0.113054

Cross-section random effects test equation:
Dependent Variable: RETURN?
Method: Panel Least Squares
Date: 09/02/16 Time: 14:28
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?

-0.590524
0.022029
-0.153278
-1.73E-06
0.012042
0.113054

0.214889
0.009425
0.129330
1.05E-05
0.005323
0.039427

-2.748041
2.337355
-1.185170
-0.164694
2.262232
2.867403

0.0070
0.0212
0.2384
0.8695
0.0256
0.0049

Effects Specification
Cross-section fixed (dummy variables)
R-squared
Adjusted R-squared
S.E. of regression
Sum squared resid
Log likelihood
F-statistic
Prob(F-statistic)

0.355807
0.165350
0.581010
38.82089
-111.4650
1.868175
0.007670

Mean dependent var
S.D. dependent var
Akaike info criterion
Schwarz criterion
Hannan-Quinn criter.
Durbin-Watson stat

0.154660
0.635963
1.952867
2.655349
2.238263
2.267490

120

Universitas Sumatera Utara

LAMPIRAN 7
HASIL PENGUJIAN PEMILIHAN MODEL DATA PANEL
DENGAN FIXED EFFECT MODEL (FEM)
Dependent Variable: RETURN?
Method: Pooled Least Squares
Date: 09/02/16 Time: 14:28
Sample: 2011 2015
Included observations: 5
Cross-sections included: 30
Total pool (balanced) observations: 150
White cross-section standard errors & covariance (d.f. corrected)
WARNING: estimated coefficient covariance matrix is of reduced rank
Variable

Coefficient

Std. Error

t-Statistic

Prob.

C
ROA?
DER?
EPS?
PER?
PBV?
Fixed Effects (Cross)
_ADES--C
_RMBA--C
_DVLA--C
_DLTA--C
_GGRM--C
_HMSP--C
_INAF--C
_ICBP--C
_INDF--C
_KLBF--C
_KICI--C
_KAEF--C
_LMPI--C
_TCID--C
_MBTO--C
_MYOR--C
_MERK--C
_SCPI--C
_MLBI--C
_MRAT--C
_ROTI--C
_PSDN--C
_PYFA--C
_SKLT--C
_STTP--C
_AISA--C
_TSPC--C
_ULTJ--C
_UNVR--C
_CEKA--C

-0.590524
0.022029
-0.153278
-1.73E-06
0.012042
0.113054

0.120999
0.008793
0.071747
5.20E-06
0.003823
0.023683

-4.880415
2.505288
-2.136365
-0.333206
3.149367
4.773573

0.0000
0.0136
0.0348
0.7396
0.0021
0.0000

-0.233450
0.489785
0.034663
-0.740602
-0.290785
-0.454549
0.649372
-0.149393
-0.338946
-0.756920
0.321903
0.507863
0.220345
-0.051238
0.152417
-0.214305
-1.064781
0.588551
-0.117938
0.048450
-0.439019
1.405576
-0.006207
0.371547
0.378349
0.159765
-0.237125
-0.121602
-0.120509
0.008785
Effects Specification

Cross-section fixed (dummy variables)

121

Universitas Sumatera Utara

R-squared
Adjusted R-squared
S.E. of regression
Sum squared resid
Log likelihood
F-statistic
Prob(F-statistic)

0.355807
0.165350
0.581010
38.82089
-111.4650
1.868175
0.007670

Mean dependent var
S.D. dependent var
Akaike info criterion
Schwarz criterion
Hannan-Quinn criter.
Durbin-Watson stat

0.154660
0.635963
1.952867
2.655349
2.238263
2.267490

122

Universitas Sumatera Utara

LAMPIRAN 8
ANALISIS DESKRIPTIF
RETURN

ROA

DER

EPS

PER

PBV

Mean

0.154660

15.73970

0.819183

1674.955

21.78404

2.340584

Median

0.024522

13.78637

0.782189

110.1392

21.59011

1.510839

Maximum

5.200000

45.72007

2.258498

55587.52

58.58105

8.994068

Minimum

-0.990042

-9.714339

-1.338314

-17350.39

-17.19549

-2.695203

Std. Dev.

0.635963

11.92168

0.584356

6773.597

14.34485

2.288365

Skewness

3.734806

0.611752

-0.223349

4.971970

-0.507545

0.941089

Kurtosis

28.68980

3.271348

4.229433

35.39909

3.846085

3.269771

Jarque-Bera

4473.505

9.816211

10.69404

7178.642

10.91417

22.59607

Probability

0.000000

0.007386

0.004762

0.000000

0.004266

0.000012

Sum

23.19900

2360.955

122.8774

251243.3

3267.606

351.0877

Sum Sq. Dev.

60.26283

21176.84

50.87938

6.84E+09

30660.44

780.2554

Observations

150

150

150

150

150

150

123

Universitas Sumatera Utara