An extremely simple procedure for the analysis of circadian and estrous periodicity

A method for the analysis of circadian and estrous periodicity based on immediate visual inspection of the data is described. The method involves the calculation of two statistics, P (the period of the oscillations in the data) and h (an index of homogeneity of P). The sampling distribution of both statistics is examined and critical values for significance tests are presented. A computational algorithm for use with large data sets is also presented. The method is intended to be not a substitute for traditional methods of time series analysis but an alternative strategy to be used in cases where a rapid and simple determination of periodicity is desired.