Representation of the output of function varbin used to estimate proportions and their variance 
             under various distribution assumptions.
Objects can be created by calls of the form new("varbin", ...) or, more commonly,
  via the function varbin.
CALLThe call of the function.
tabA data frame containing the estimates, their variance and the confidence limits.
pbootA numeric vector containing the bootstrap replicates.
alphaThe \(\alpha\) level to compute confidence intervals.
featuresA named numeric vector summarizing the design.
signature(object = "varbin"): see varbin.