Fault tree analysis

[Indy]

Hi,
I am new to fault trees and I’m currently carrying out some background reading to aid my understanding. I have a question about calculating various values

Q
r
W
I know Q is the unavailability, r is the failure rate per hour and w is the frequency.

If given r only how does one calculate Q? I have seen the formula Q=1-e^-lamda(T) but not sure where r and w come into this ?


Thanks