Definition

The probability that a point measurement lies within a specific range of area-average (volume-average) concentration value

Source

Nappo [RD14]

RD14: Nappo, C.J., Caneill J.Y., Furman R.W., Gifford F.A., Kaimal J.C., Kramer M.L., Lockhart T.J., Pendergast M.M, Pielke R.A., Randerson D., Shreffler J.H., and Wyngaard J.C., The Workshop on the Representativeness of Meteorological Observations, June 1981, Boulder, CO, Bull. Am. Meteorol. Soc. 63, 761-764, 1982. 

Suggestions

Again, applies to one community (concentration measurements) only. It should be possible to consider this from other fields too