In a memory test, the test subjects are given a large number and are asked to memorize it. Historical records show that 60% 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 600 people to take the memory test is going to be chosen. Let 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 O (b) Find the standard deviation of p. (c) Compute an approximation for P(p