Perhatikan tabel distribusi frekuensi variabel acak X

Perhatikan tabel distribusi frekuensi variabel acak X berikut!
x12345678P(X = x)1/121/121/81/61/61/81/121/6
Tentukan nilai:
a.P(X ≤ 3)
b.P(X ≤ 5)
c.P(4 ≤ X ≤ 7)
Jawab:
a.P(X ≤ 3) = f(1) + f(2) + f(3)
= 1/12 + 1/12 + 1/8
= 2/24 + 2/24 + 3/24
P(X ≤ 3) = 7/24