The simulated data consists of 1000 time series (genes). The total number of periodic genes is 100. P is the number of periodic genes that are statistically significant for a FDR level of q = 0.02. The number of false positives FP can be computed as FP = q*TP/(1-q), where TP is the number of true positives. Keeping q at a fixed level ensures that we do not sacrifice specificity for sensitivity.