VGAM (version 0.8-1)

snorm: Skew-Normal Distribution

Description

Density and random generation for the skew-normal distribution.

Usage

dsnorm(x, location = 0, scale = 1, shape = 0, log = FALSE)rsnorm(n, location = 0, scale = 1, shape = 0)

Arguments

x

vector of quantiles.

n

number of observations. Must be a single positive integer.

location

The location parameter $\xi$. A vector.

scale

The scale parameter $\omega$. A positive vector.

shape

The shape parameter. It is called $\alpha$ in skewnormal1.

log

Logical. If log=TRUE then the logarithm of the density is returned.

Value

• dsnorm gives the density, rsnorm generates random deviates.

Details

See skewnormal1, which currently only estimates the shape parameter. More generally here, $Z = \xi + \omega Y$ where $Y$ has a standard skew-normal distribution (see skewnormal1), $\xi$ is the location parameter and $\omega$ is the scale parameter.

References

http://tango.stat.unipd.it/SN.

See Also

skewnormal1.

Examples

n = 200   # grid resolution
shape = 7
x = seq(-4, 4, len=n)
plot(x, dsnorm(x, shape=shape), type="l", col="blue", las=1, ylab="")
abline(v=0, h=0, lty="dashed", col="darkgreen")
lines(x, dnorm(x), col="red")
legend(-3.5, 0.6, leg=c(paste("Blue = dsnorm(x, ", shape,")", sep=""),
       "standard normal density"), lty=1, col=c("blue","red"))