public class WilcoxonTestextends StatisticalTestThe Wilcoxon Signed-Ranks test This test is proposed for use with paired-sample data in making inferences concerning the value of the median of the population of differences. Zero differences are shared between both samples. If there is a odd number of them, one is discarded. Ties are handled by the midrank method. An exact p-value (for p-values equal or lower than 0.2, and sample size equal or lower than 50) is provided. An asymptotic approximation to the normal distribution is also provided. Furthermore, this version of the test also provides two confidence intervals (at 0.90 and 0.95 levels) for the location of the median of the differences, through the use of Walsh averages.