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PEMBAHASAN STATISTIKA KELAS XI

Oleh: Erni Kundiarsih

MATEMATIKANET.COM

1. Rata-rata = � � � � � � � � � � � � � � � � � � � � � � � � � � �

� = ��� = 7

2. Median = � � �

= 7

3. Modus = 7

4. Jangkauan = 9 – 5 = 4

5. Mean = � � � � � � � � � � � � � � � � � � ��

�� = 7

Median = 6

Modus = 6

6. Mean = � � � � � � � � � � � � �

� = 6

Median = ���

� 6

Modus = 6

7. Rata-rata = ��� � ����� � ���� � ������ � ���� � ����

� = .���

� = 65 kg

8. Mo = 64,5 � � �� 5 = 64,5 + 2,5 = 67

9. Kuartil atas = � x 40 = 30

�� = �� � ��� ∑ ��� �

�!�" #

= 69,5 � ���.���

� " 5

= 69,5 + 1,25

= 70,75

10. % � � � ��&'() ��*

� " +, = 59,5 � ��&�)() ���

� " +5 = 63,25

11. 6 � � � � � � � - � � � � � � � � � � ��

a = 10

12. ����� � ��.� � ����� � ����� � ����

��/ = 48

1.326 + 43 x = 48 ( 27 + x )

1.326 + 43 x = 1.296 + 48 x

2

5x = 30

x = 6

13. Data setelah diurutkan:

5 6 7 7 8 9 10 12 14

�� � ��

Kuartil bawah = � � �

= 6,5

14. Kuartil atas = �� � �

= 11

15. %� � �� � �0&'() ��*

� " +, = 55,5 � �0&�)() ��

� " +5 = 58

16. Nilai rata-rata = 6�22� � 10�27� � 2�32� � 5�37� � 4�42� � 3�47�

�� = ����� = 32

17. Modus

Mo = � � � 6(6(�67� # = 24,5 � �

��� 5 = 24,5 � � �� 5 = 26,2

18. Media

� = � � �(7 ∑ ��� 7

�89: " #

= 24,5 � �(7.����

�� " 5

= 24,5 � ��� . 5

= 29

19. Kuartil atas

�� = �� � ��� ∑ ��� �

�!�" #

= 34,5 � ���.�����

� " 5

= 34,5 + 4,5

= 39

20. Kuartil bawah

�� = �� � �(� ∑ ��� (

�!(" #

= 24,5 � �(�.����

�� " 5

= 24,5 + 0,75

3

= 25,25

21. Simpangan kuartil

�6 = � ��� ; ��) =

� �39 ; 25,25) = 6,875

22. Rata-rata data tersebut adalah 7

sehingga diperoleh ragam S2, yaitu

S2 = �� ��4 ; 7� � �8 ; 7� � �5 ; 7� � �9 ; 7� � �10 ; 7� � �6 ; 7��

= �� (9 + 1 + 4 + 4 + 9 + 1)

= 4,67

S = √4,67 = 2,16

23. ��� � ���� � ���� � ��>� � ���

�� �? = 7

121 + 8 M = 7 ( 19 + M)

121 + 8 M = 133 + 7M

M = 12

24. . � �. � � � �. � ��

� = 24

3x + 9 = 24 . 3

3x = 72 – 9

x = 21

25. ����.���� � ���.���� � ����.���� � ����.���� � ���.����

�� = ����� = 7.420

26. +@ � /@(.�(�/@7.�7�(��7

7,5 � �,�.��/@7.����

7,5 � ����/@7.��

240 = 156 + +@ . 12

12 +@ = 84

+@ = 7

27. +@ � /@(.�(�/@7.�7�(��7

6,6 � �,�.�(�� .��(��

6,6 A� + 6,6 = 6,5. A� � 9 . 1

0,1 A� = 2,5

A� = 25

4

28. Rata-rata = +@ = �� � ���� � ���� � ����� � ���

�� = � � � � � � �� � �

�� = ����� = 6,3

Siswa dinyatakan lulus ujian matematika jika nilainya lebih besar dari 6,3.

Jadi, jumlah siswa yang lulus adalah 11 + 4 = 15 siswa

29. Nilai total kelompok = 50 x 64 = 3.200

Nilai rata-rata 49 siswa = �.�����,�

� = 63,5

30. Misal:

Jumlah siswa laki-laki = a

Jumlah siswa perempuan = b

��B��CB�C � 58

65a + 54 b = 58a + 58b

7a = 4b

b : a = 7 : 4