Granger causality and Bayesian network inference applied on data points of various sample sizes. The grey edges in the inferred network structures indicate undetected causalities in the toy model. For each sample size n, we simulated a data set of 100 realizations of n time points. The Bayesian network structure represents a model average from these 100 realizations. High-confidence arcs, appearing in at least 95% of the networks are shown. The Granger causality inferred the structure according to the 95% confidence interval constructed by using the bootstrap method. (A) The sample size is 80. (B) The sample size is 60. (C) The sample size is 20.