The outage probability of a diversity combiner is defined as the percentage of time the instantaneous output SNR of the combiner is below some prescribed level for a specified number of diversity branches. Consider a communication system that employs multiple receiver antennas to achieve diversity in a Rayleigh fading channel. Suppose that selection diversity is used with Nr receiver antennas. If the average SNR is 20 dB, determine the probability that the instantaneous SNR drops below 10 dB when 1. Nr = 1 2. Nr = 2 3. Nr = 4