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Empirical research on stock market data for two consecutive trading days indicates that 50% of the stocks that went up on the first day also went up on the second day. Yesterday, 400 stocks went up. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p, where p gives the proportion of the 400 stocks that went up yesterday that will go up today. X 5 ? (b) Find the standard deviation of p (c) Compute an approximation for P (p