Abstract
The fect that departures from average density, pressure and temperature in the atmosphere are very small compared to their average values makes it possible to use a perturbation form of the equation of state to construct algebraic relations among statistics involving these quantities. It is shown how these relations can simplify statistical computations. In particular, where density is one parameter concerned, it is not necessary to compute density from pressure and temperature for each observation. The statistical parameters on temperature and pressure (the quantities always available) and the derived algebraic relations permit the determination of the statistics involving density.
