A radar works by transmitting pulse, and detecting whether there is echo. Ideally, an echo points to that the object is present, while no echo means no object. But, some echoes may get lost, and others might be generated because of other surfaces. To enhance accuracy, a radar transmits n pulses, where n is fixed number, and sees how many echoes it gets. It then makes a decision based upon this number. Let p1 be the probability of an echo for single pulse when there is no object, and p2 be the probability when there is object. Suppose p1 < p2. What is the ML estimation rule based upon the echo observations for whether object is present or absent?