Page 14 - E-Modul Statistika

Nilai rata-rata = X1 + X2 + X3 + X4 + X5 + X6

6
= 8 + 7 + 5 + 7 + 6 + 9
6

= 7
Sehingga nilai rata-ratanya adalah 7

3. Kelas 5A diketahui berjumlah 20 siswa, setelah melaksanakan ujian

Matematika, mereka memperoleh beragam nilai yakni 5.5, 7, 8, 7.5, 9,
4, 6, 7, 4, 7, 8, 6, 6.5, 6, 5, 9, 8, 9, 7, 5. Berapakah nilai rata-rata kelas

5A?
Pembahasan
Diketahui : X1 = 5.5 X11 = 8

X2 = 7 X12 = 6
X3 = 8 X13 = 6.5

X4 = 7.5 X14 = 6
X5 = 9 X15 = 5
X6 = 4 X16 = 9

X7 = 6 X17 = 8
X8 = 7 X18 = 9

X9 = 4.5 X19 = 7
X10 = 7 X20 = 5

Ditanya: X ......?
Jawab : X = (X1 + X2 + X3 + X4 + X5 + X6 + X7 + X8 + X9 + X10 + X11 +

X12 + X13 + X14 + X15 + X16 + X17 + X18 + X19 + X20)
20
= (5.5 + 7 + 8 + 7.5 + 9 + 4 + 6 + 7 + 4.5 + 7 + 8 + 6 + 6.5 + 6 + 5

+ 9 + 8 + 9 + 7 + 5)
20

= 135
20

= 6.75
Nilai rata-rata kelas 5A adalah 6.75

7