In many problems, the statistician may believe it unlikely that the data will ever exceed a certain value or drop below another, although there are no theoretical limits on the variable being modeled. This information could, and perhaps should, be used in statistical modeling; if not,...

A method of jointly estimating the time-dependent variance of daily commodity price changes and their distribution is presented. The data are copper spot prices (1966-74) and sugar futures prices (1961-73), for London contracts. Much of the leptokurtosis observed in the price change...