A subject is allowed a sequence of glimpses to detect a target . Let Gi = {the target is detected on the ith ?glimpse},with pi ?= ?P?(?Gi?). ?Suppose the ?Gi ' ?s are independent events, and write an expression for the probability that the target has been detected by the end of the ?n?th glimpse. [?Note: ?This model is discussed in “Predicting Aircraft Detectability,” ?Human Factors, ?1979: 277–291.]

Solution: Step 1 : Here it is given that a subject allowed a sequence of glimpses to detect a target. Gi is the event defined as Gi={the target is detected on the ith glimpse}, with pi=P(Gi). It is also given that Gi’ s are independent events. We have to write an expression for target has been detected at the end of the nth glimpse.