The test is not as important as the confidence intervals, which are often used for directly standardized rates. The default uses the gamma method by fay and Feuer (1997), which by all simulations appears to retain nominal coverage for any set of parameters or weights. There is a mid-p-like version that is less conservative.
Calculates the exact Wilcoxon signed rank test (using Pratt's method if there are zero values). Gives exact matching confidence intervals based on repeated calls to wilcoxsign_test.
The ath quantile of a distribution is the value, q, such that F(q-) <= a <= F(q), where F(x)=Pr[X <= x]. These are exact tests and confidence intervals on independent observations that do not any assumptions on the distribution, F. For example, the tests are exact when data are discrete or continuous, and when the distribution is non-symmetric.
providing 
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