Basic Concepts F(t)denotes the probability that the item fails in time interval(0,T f(t)is the probability density function of T. Fo=Pr(T≤)={fod The reliability function of an item is given as, R(t)=1-F(t)=Pr(T>t) or equivalently, R()=f(u)du The R(t)is also called the survivor function. R(t)is the probability that the item does not fail in(0,t]. CLGO System Engineering by J.J.Gao 11+ - System Engineering by J. J. Gao 11 Basic Concepts