Latihan Soal Regresi dan Kolerasi Linear Sederhana

SOAL :

X	65	63	67	64	68	62	70	66	68	67
Y	68	64	69	65	67	66	68	65	70	67

PERTANYAAN :
a. Gambarkan Dalam Scatter Diagram ?
b. Carilah KK dan Jelaskan Artinya ?
c. Carilah Koefisien Determinasi ?

JAWABAN :

Data (N)	X	Y	X.X	Y.Y	X.Y
1	65	68	4225	4624	4420
2	63	64	3969	4096	4032
3	67	69	4489	4761	4623
4	64	65	4096	4225	4160
5	68	67	4624	4489	4556
6	62	66	3844	4356	4092
7	70	68	4900	4624	4760
8	66	65	4356	4225	4290
9	68	70	4624	4900	4760
10	67	67	4489	4489	4489
Jumlah	660	669	43616	44789	44182

a. Diagram Scatter

b. KK = [(N . ΣXY) – (ΣX . ΣY)] / √ [ (N . ΣX2) – (ΣX)2] . [(N . ΣY2) – (ΣY)2]
= [(10(44.182)) - (660)(669)] / √ [(10 (43.616) - (660)2)(10(44.789) - (669)2)]
= 441.820 - 441.540 / √ (436.160 - 435.600) (447.890 - 447.561)
= 280 / √ (560) (329)
= 280 / √ (184.240)
= 280 / 429,23 = 0,65
Artinya :
Jenis Korelasi = Korelasi Positif
Tingkat Keeratannya = Kuat

c. KP = [((N . ΣXY) – (ΣX)(ΣY))2] / [(N . ΣX2) – (ΣX)2] . [(N . ΣY2) – (ΣY)2]
= [((10(44.182) - (660)(669))2]/[(10(43.616) - (660)2)(10 (44.789) - (669)2)]
= (441.820 - 441.540)2 / (436.160 - 435.600) (447.890 - 447.561)
= (280)2 / (560) (329)
= 78.400 / (184.240) = 0,43
Jadi, KP = 0,43 (43%).