A program consists of two modules

[TomJerry]

Question:
A program consists of two modules. The number of errors X in the first module and the number of errors in the second module have the joint distribution:

P(0,0) = P(0,1) = P(1,0) = 0.20
P(1,1) = P(1,2) = P(1,3) = 0.10
P(0,2) = P(0,3) = 0.05

Find
i) the marginal distribution of X and Y
ii) the probability of number errors in the first module.
iii) the probability distribution of total number of errors in the program.
iv) if the errors in the two modules occur independently


Solution

i)
h(y) = 0.40 + 0.30 + 0.15 + 0.15 Is this correct

&

g(x) = 0.50 + 0.50 Is this correct

ii)
g(x) = 0.50 + 0.50 Is this correct

iii)
total = 1 Is this correct

iv)
stuck here