A multiple -choice examination consist of 85 questions, each having possible choices a, b, c, and d. Approximate the probability that a student will get at least 23 answers correct if he randomly guesses at each answer. ( Note that, if he randomly guesses at each answer, then the probability that he gets any one answer correct is 0.25). Use the normal approximation to the binomial with a correction for continuity.

Round your answer to at least 3 decimal places. Do not round any intermediate steps.