This document contains a summary of the mid-term exam for the Communication Networks course EE 333. The exam has 3 questions. Question 1 involves analyzing the average efficiency of a new Automatic Repeat reQuest (ARQ) technique for different block sizes. Question 2 involves cyclic redundancy checks (CRC) coding and analyzing whether a received code word contains errors. Question 3 involves analyzing a 3-user Slotted ALOHA system and deriving state transition probabilities and maximum throughput.