Plot Parametric Density Functions

These are utilities for pretty plotting of often used parametric densities.

p.dnorm (mu = 0, s = 1, h0.col = "light gray",
         ms.lines = TRUE, ms.col = "gray", ...)
p.dchisq(nu,    h0.col = "light gray", ...)
p.dgamma(shape, h0.col = "light gray", ...)

Arguments

mu,s

numbers, the mean and standard deviation of the normal distribution.

nu

positive number, the degrees of freedom df argument for the \(\chi^2\)-density function dchisq.

shape

number, the shape parameter for the Gamma distribution.

h0.col

color specification for the line \(y = 0\).

ms.lines

logical, used for the normal only: should lines be drawn at the mean and \(\pm\) 1 standard deviation.

ms.col

color for the ms lines if ms.lines is TRUE.

...

further parameter passed to curve(), e.g., add = TRUE for adding to current plot.

Author

Werner Stahel et al.

See also

the underlying density functions, dnorm, dchisq, dgamma.

Examples

p.dnorm()
p.dnorm(mu=1.5, add = TRUE, ms.lines = FALSE) # add to the plot above


p.dchisq(2, main= "Chi^2 Densities -- nu = 2,3,4")
p.dchisq(3, add = TRUE, col = "red")
p.dchisq(4, add = TRUE, col = "blue")


op <- par(mfrow = c(2,2), mgp = c(1.6, 0.6,0), mar = c(3,3,1,1))
for(sh in 1:4)
   p.dgamma(sh)

par(op)