Obtains the quantiles of a survival distribution.
fquantile(S, probs, ...)A vector of length(probs) for the quantiles.
fquantile(pweibull, probs = c(0.25, 0.5, 0.75),
shape = 1.37, scale = 1/0.818, lower.tail = FALSE)
#> [1] 0.4923723 0.9355369 1.5516430