Answer:
Step-by-step explanation:
Given that X is the number of months between successive payments
Cumulative distribution function of X is
[tex]F(x) =0, x<1\\F(x) = 0.33, 1<x<3\\F(x) =0.44, 3<x<4\\F(x) = 0.48, 4<x<6\\F(x) = 0.86, 6<x<12\\F(x) = 1, X>12\\[/tex]
a) PMF of x would be
[tex]P(x) =0, x<1\\P(x) = 0.33, 1<x<3\\P(x) =0.11, 3<x<4\\F(x) = 0.04, 4<x<6\\F(x) = 0.38, 6<x<12\\P(x) = 0.14,\\ X>12[/tex]
b) [tex]P(3 ≤ X ≤ 6) =0.86-0.44=0.42\\ P(4 ≤ X)=1-0.44=0.56\\P(3 < X < 6) =0.6\\P(4 < X) =1-0.48=0.52[/tex]