I am trying to do the following question:
The lifetime X (in years) of an item has a rate function
λX(t)=t2+t4fort>0. What is the probability that
a) an item survives to age 1?
b) an item’s lifetime is between .5 and 1.5?
c) a 1/2 year old item will survive to age 1?
d) Now suppose the rate has doubled and let Y be the new lifetime with respect to the rate function
2λX(t).
What is
P(Y>1∣Y>.5)?
I'm not sure how to tackle this question. In my book it says that the hazard rate function is defined by
λ(t)=Fˉ(t)f(t)whereFˉ=1−F but the rate function we are given isn't similar to this form? I suppose I'm suppose to use the rate function in the exponential distribution. The book gives a very small explanation about hazard rate functions, and only one example so I'm having a hard time understand it. Please help!