The (+) reference: accuracy of estimated mean components in average response studies.

The (+/-) reference is defined as the result of alternate addition and subtraction and division by N (the number of sample functions). Under suitable conditions both the (+/-) reference and the variable component (noise) of the usual average tend to be derived from the same Gaussian process, and the former can be used as a measure of the latter. This property is most easily applied when the noise is derived from a stationary process. Application of the (+/-) reference and the average of the square of the voltage in studies of evoked response is discussed.