An obsolete 2400 bps modem uses QAM (see Problem 8.3.4) to transmit one of 16 symbols, s0,...,s15, every 1/600 seconds. When signal si is transmitted, the receiver output is

(a) Sketch the acceptance sets based on the receiver outputs X1, X2
(b) Let Hi be the event that symbol si was transmitted and let C be the event that the correct symbol is decoded. What is P[C|H1]?
(c) Argue that P[C] ≥ P[C|H1].