1
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 )
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
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
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 C
B C 58
65a + 54 b = 58a + 58b 7a = 4b
