Question

whats the P(X1+X2=1)?

Answer 1

\[P(X_1+X_2=1)\]

\[=P([X_1=0,X_2=1] \text{ or } [X_1=1,X_2=0])\]

Answer 2

can you explain more?

Answer 3

In which cases can X1+X2 amount to one? Look at the table and see that it happens only when: (X1=1 AND X2=0) OR (X1=0 AND X2=1)
P [(X1=1 AND X2=0) OR (X1=0 AND X2=1)]=P(X1=1 AND X2=0)+P(X1=0 AND X2=1)=
2/12+3/12=5/12