When calculating a moving average, a mathematical analysis of the security's average value over a predetermined time period is made. As the security's price changes, its average price moves up or down. Instead of the traditional transaction of buying at a lower price and profiting by selling at a higher price, the short sale transaction is just the opposite. On Balance Volume was developed by Joe Granville and originally presented in his book New Strategy of Daily Stock Market Timing for Maximum Profits. An open contract can be a long or short contract that has not been exercised, closed out, or allowed to expire.
Open interest is really more of a data field than an indicator.
The Black-Scholes model helps determine the fair market value of an option based on the security's price and volatility, time until expiration, and the current market interest rate. This indicator is explained thoroughly in Wilder's book, New Concepts in Technical Trading Systems.