Answer:
Step-by-step explanation:
Hello!
To know what will be the resulting E(X) and V(X) of the total volume shipped, you have to add the three variables.
According to the properties of the E(X) The expected value of two variables or more independent variables is equal to the addition of the expected values of each variable: X+Y⇒ E(X+Y)= E(X) + E(Y)
In this case:
E(X₁+X₂+X₃)= E(X₁)+E(X₂)+E(X₃)= 200 + 240 + 120= 560 ft³
The same happens with the variance, if you add two independent variables, the variance of the resulting variable will be equal to the addition of the variance of each variable: X+Y ⇒ V(X+Y)= V(X)+V(Y)
In this case:
V(X₁+X₂+X₃)= V(X₁)+V(X₂)+V(X₃)= 10+13+8= 31
I hope it helps!
