2. Underwater acoustic communication. A subcarrier is one telecommunication signal carrier that is carried on top of another carrier so that effectively two signals are carried at the same time....

Please answer a-c. Thanks

Extracted text: 2. Underwater acoustic communication. A subcarrier is one telecommunication signal carrier that is carried on top of another carrier so that effectively two signals are carried at the same time. Subcarriers can be used for an entirely dif- ferent purpose than main carriers. For example, data sub- carriers are used for data transmissions; pilot subcarriers are used for channel estimation and synchronization; and, null subcarriers are used for direct current and guard banks transmitting no signal. In the IEEE Journal of Oceanic Engineering (April, 2013), researchers studied the characteristics of subcarriers for underwater acoustic communications. Based on an experiment conducted off the coast of Martha's Vineyard (MA), they estimated that 25% of subcarriers are pilot subcarriers, 10% are null sub- carriers, and 65% are data subcarriers. Consider a sample of 50 subcarriers transmitted for underwater acoustic com- munications. a. How many of the 50 subcarriers do you expect to be pilot subcarriers? Null subcarriers? Data subcarriers? b. How likely is it to observe 10 pilot subcarriers, 10 null subcarriers, and 30 data subcarriers? c. If you observe more than 25 pilot subcarriers, what would you conclude? Explain.