Question: The associated Press reports that the mean trading Volume for equity and index options contracts was 3.6 million in July 2007. Assume that the distribution is normal with a mean µ = 3.6 (in millions) and standard deviation is σ = 0.5 (in millions).
a) Find the probability that a randomly selected trading value exceeds 4.1 million.
b) Find the trading volume greater than 90% of all trading volumes. Use formula X1 = Z σ + µ