In a memory test, the test subjects are given a large number and are asked to memorize it. Historical records show that 80% of test subjects pass the test. To pass the test, a subject must exactly repeat all the digits in the number after two hours. A random sample of 625 people to take the memory test is going to be chosen. Let p be the proportion of people in the sample who pass the test. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p. X 0 (b) Find the standard deviation of p. (c) Compute an approximation for P (p > 0.84), which is the probability that more than 84% of the people in the sample pass the test. Round your answer to four decimal places