#69 Exponential Distri

[dragonfromtheeast]

Hi Guys,
I have some difficulty to solve below problem, I have no clue how to approach it. Would someone help me out. Thanks D.T

Q: The time to failure of a component in an electronic device has an exponential distribution with a median of four hours.

Calculate the probability that the component will work without failing for at least five hours.

[Gandalf]

They are saying F(4) = .5 (because 4 is the median) and asking what S(5) = 1- F(5) is.

From F(4) = .5, you need to find the parameter for the exponential distribution (i.e., is this an exponential distribution with mean 3, with mean 17, or what?) Then you can get F(5).