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Var (S ) =Var (NX ) =Var (N )E^2 ( X ) + E (N)Var ( X )
This is a formula Guo gives for solving a geometric problem-
N is the number of problems in a year, and X is the amount of the loss
(N is the geometric part, N and X are independent)
Where does this formula come from?
(It's on page 126 -127 of the current manual, in the section on Geo. random vars, problem 3)
He says we should memorize it.
This is a formula Guo gives for solving a geometric problem-
N is the number of problems in a year, and X is the amount of the loss
(N is the geometric part, N and X are independent)
Where does this formula come from?
(It's on page 126 -127 of the current manual, in the section on Geo. random vars, problem 3)
He says we should memorize it.
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