Shading functions for interpretation of pdf probabilities

Creates plots with lower, upper, two-tailed, and middle of the distribution shading for popular pdfs.

shade.norm(x = NULL, from = NULL, to = NULL, sigma = 1, mu = 0,
  tail = "lower", show.p = TRUE, show.d = FALSE, show.dist = TRUE,
  digits = 5, legend.cex = 0.9, shade.col = "gray", ...)

shade.t(x = NULL, from = NULL, to = NULL, nu = 3, tail = "lower",
  show.p = TRUE, show.d = FALSE, show.dist = TRUE, digits = 5,
  legend.cex = 0.9, shade.col = "gray", ...)

shade.F(x = NULL, from = NULL, to = NULL, nu1 = 1, nu2 = 5,
  tail = "lower", show.p = TRUE, show.d = FALSE, show.dist = TRUE,
  prob.to.each.tail = 0.025, digits = 5, legend.cex = 0.9,
  shade.col = "gray", ...)

shade.chi(x = NULL, from = NULL, to = NULL, nu = 1,
  tail = "lower", show.p = TRUE, show.d = FALSE, show.dist = TRUE,
  prob.to.each.tail = 0.025, digits = 5, legend.cex = 0.9,
  shade.col = "gray", ...)

Arguments

x	A quantile, i.e. \(X = x\), or if tail = "two.custom" ins shade.norm, a two element vector specifying the upper bound of the lower tail and the lower bound of the upper tail.
from	To be used with tail = "middle"; the value a in \(P(a < X < b)\).
to	To be used with tail = "middle"; the value b in \(P(a < X < b)\).
sigma	Standard deviation for the nomral distribution.
mu	Mean of the normal distribution.
tail	One of four possibilities: "lower" provides lower tail shading, "upper" provides upper tail shading, "two" provides two tail shading, and "middle" provide shading in the middle of the pdf, between "from" and "to". The additional option "two.custom" is allowed for shade.norm. This allows calculation of asymmetric two tailed probabilities. It requires that the argument x is a two element vector with elements denoting the upper bound of the lower tail and the lower bound of the upper tail. For discrete pdfs (binomial and Poisson) the possibility "X=x" is also allowed, and will be equivalent to the density. Two tailed probability is not implemented for shade.poi.
show.p	Logical; indicating whether probabilities are to be shown.
show.d	Logical; indicating whether densities are to be shown.
show.dist	Logical; indicating whether parameters for the distribution are to be shown.
digits	Number of digits to be reported in probsabilities and densities.
legend.cex	Character expansion for legends in plots.
shade.col	Color of probability shading.
...	Arguments to be passed to methods, such as graphical parameters (see par).
nu	Degrees of freedom.
nu1	Numerator degrees of freedom for the F-distribution.
nu2	Denominator degrees of freedom for the F-distribution.
prob.to.each.tail	Probability to be apportioned to each tail in the F and Chi-square distributions if tail = "two".