snorm {VGAM}R Documentation

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 w. 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.

Details

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

Value

dsnorm gives the density, rsnorm generates random deviates.

Note

The default values of all three parameters corresponds to the skew-normal being the standard normal distribution.

Author(s)

T. W. Yee

References

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

See Also

skewnormal1.

Examples

## Not run:  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 = "", lty = 1, lwd = 2)
abline(v = 0, h = 0)
lines(x, dnorm(x), col = "orange", lty = 2, lwd = 2)
legend("topleft", leg = c(paste("Blue = dsnorm(x, ", shape,")", sep = ""),
       "Orange = standard normal density"), lty = 1:2, lwd = 2,
       col = c("blue", "orange")) 
## End(Not run)

[Package VGAM version 0.8-4 Index]