Illustrated quantile calculations from distributions
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dist 
a character discription of a distribution, for example

p 
a vector of probabilities 
plot 
a logical indicating whether a plot should be created 
verbose 
a logical 
invisible 
a logical 
resolution 
number of points used for detecting discreteness and generating plots. The defaut value of 5000 should work well except for discrete distributions that have many distinct values, especially if these values are not evenly spaced. 
digits 
the number of digits desired 
xlim 
x limits. By default, these are chosen to show the central 99.8% of the distribution. 
ylim 
y limits 
vlwd 
width of vertical lines 
vcol 
color of vertical lines 
rot 
angle for rotating text indicating probability 
... 
additional arguments, including parameters of the distribution and additional options for the plot 
The most general function is qdist
which can work with
any distribution for which a qfunction exists. As a convenience, wrappers are
provided for several common distributions.
a vector of quantiles; a plot is printed as a side effect
1 2 3 4 5 6 7 8  qdist("norm", seq(.2, .8, by = 0.10))
xqnorm(seq(.2, .8, by = 0.10), mean = 100, sd = 10)
qdist("unif", .5)
xqgamma(.5, shape = 3, scale = 4)
xqchisq(c(.25,.5,.75), df = 3)
xpbinom( c(480, 500, 510), size = 1000, prob = 0.48)
xpbinom( c(40, 60), size = 100, prob = 0.5)
xqpois( c(0.25, 0.5, 0.75), lambda = 6, lwd = 3, vlwd = 2)

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