  We use the expectation of the range of an arithmetic Brownian motion and the
method of moments on the daily high, low, opening and closing prices to
estimate the volatility of the stock price. The daily price jump at the opening
is considered to be the result of the unobserved evolution of an after-hours
virtual trading day.The annualized volatility is used to calculate
Black-Scholes prices for European options, and a trading strategy is devised to
profit when these prices differ flagrantly from the market prices.
