The bootstrap method is based on a creation of more B selections with extend of n based on the original selection
with the same extend of n. New selections are determined by the selection of elements from the original set with
replication (Leng, Tsai, 2014). Then the statistical analysis is realized on the basis of statistics calculated from these
B bootstrap selections. Thus, we can obtain relatively reliable results without any restrictive assumptions. The
following table depicts the basic principle of bootstrap method.