Z-squared statistics for three cases. The green line shows the Z-squared statistic for a Poisson sample. The blue line shows the statistic for a periodic signal, where the period for each datapoint is drawn from a Gaussian distribution centred at 7 h^-1 Mpc with a standard deviation of 0.5 h^-1 Mpc. The red line shows the statistic for data points with an uniform point distribution – see text for more information.