Comparison of tim-luc; cry+ foreleg specimens illustrates rhythmicity with or without statistical significance. From left to right: the first column shows raw data on the ordinate plotted over time on the abcissa, the second column shows detrended and normalized data plotted over time and the third column shows autocorrelation with p = 0.05 confidence interval depicted by a gray area centered at 0. The top row shows the analysis of a pair of forelegs with robust rhythmicity. The autocorrelation function is significantly rhythmic as indicated by the asterisk and the strength of rhythmicity (RI) is 0.52 (see ). The bottom row shows a signal with weaker rhythmicity. While the shape of the data plots and the autocorrelation function is consistent with a rhythmic signal, the height of the third peak (with asterisk) fails to achieve statistical confidence. At 0.05, the RI is an order of magnitude weaker than the signal shown in the top row. Nevertheless, this signal is tabulated as rhythmic (see text and  for further detail).