- #1

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P(X>x)=e^-ax, x less/equal 0

Where a is a positive constant. Find EX and Var(x)

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- Thread starter badgerbadger
- Start date

- #1

- 7

- 0

P(X>x)=e^-ax, x less/equal 0

Where a is a positive constant. Find EX and Var(x)

- #2

HallsofIvy

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Now just use the definitions:

[tex]E(x)= -a \int_x^0 xe^{-ax}dx[/itex]

and

[tex]Var(x)= -a \int_x^0 (x- E(x))^2e^{-ax}dx= -aE(x)\int_x^0 x^2e^{-ax}- E^2(x)[/tex]

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