Question

Bantu no 7 ,11,12,10

Sekalian jalan

Answer 1

Verified answer

Bab Statistik
Matematika
Kelas 9 SMP

Penyelesaian

7||

Diketahui data,
6, 5, 7, 4, 9, 8, 8, 10, 9, 12, 13, 8, 8, 11, 7


Mean = jumlah data/banyak data

Mean = 6 + 5 + 7 + 4 + 9 + 8 + 8 + 10 + 9 + 12 + 13 + 8 + 8 + 11 + 7
             -------------------------------------------------------------------------------
                                                 15

Mean = 125/15

Mean = 8,34


Banyak data yang kurang dari 8,34
6, 5, 7, 4, 8, 8, 8, 8, 7
n = 9       (D)


10||

Banyak siswa yang mendapat nilai kurang dari 7 (perhatikan frekuensi)
-> nilai 3, 4, 5, 6
= (1 + 3 + 5 + 8)
= 17 siswa      (C)


11||

Mean= (60 x 2) + (65 x 2) + (70 x 3) + (75 x 4) + (80 x 3) + (85 x 4) + (90 x 2)
            -------------------------------------------------------------------------------------------
                                               2 + 2 + 3 + 4 + 3 + 4 + 2


Mean = 120 + 130 + 210 + 300 + 240 + 340 + 180
              -------------------------------------------------------
                                           20

Mean = 1520/20

Mean = 76

Nilai kurang dari rata-rata
-> 60, 65, 70
= (2 + 2 + 3)
= 7 orang            (B)


12||

Mean = Jumlah data/banyak data

7,5    = (5 x 3) + (6 x 5) + (7 x 6) + (8 . t) + (9 x 4) + (10 x 3)
            --------------------------------------------------------------------
                             3 + 5 + 6 + t + 4 + 3

7,5    = 15 + 30 + 42 + 8t + 36 + 30
            ------------------------------------
                           21 + t

7,5 (21 + t)    = 153 + 8t
157,5 + 7,5t  = 153 + 8t
157,5 - 153   = 8t - 7,5t
             4,5   = 0,5t
                9   = t      (D)


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