Ty has a 50% chance of answering a trivia question correctly. He wants to know the probability that he will answer 3 of 4 trivia questions correctly. He flips a coin to conduct the simulation shown below.
 HHTH HHIT THHT HHHH THỊT
 THHT THHT HITH THIT HHHH
 THTT THTT HTHT HHTT THTT
 TTHT HHTH THHT HHIT THTH
 H represents a correct answer, and T
 represents an incorrect answer. Based on this simulation, what is the probability that he answers at least 3 trivia questions correctly?