Nonlinear uncertainty of the long term average level calculated from short term average sound levels

Determining of the long-term average sound level, LAeqT, requires continuous noise measurement over a long time period. To decrease the cost of measurement, LAeqT is approximated by a few, m, short-term average sound levels, LAeq,t, so that mt « T. The linear and the nonlinear uncertainty of LAeq,T approximation is discussed. For a few measurements, m < 10, the nonlinear uncertainty is required.