R: Ratio of Normal Mixture to Corresponding Normal

r.norMix {nor1mix} | R Documentation

## Ratio of Normal Mixture to Corresponding Normal

### Description

Compute r(x) = f(x)/ f0(x) where f() is a normal mixture density and f0 the normal density with the same mean and variance as f.

### Usage

    r.norMix(obj, x = NULL, xlim = NULL, n = 511, xy.return = TRUE)

### Arguments

`obj` | an object of class `norMix`.
`x` | numeric vector with abscissa values where to evaluate the density. Default is constructed from `n` (and `xlim` if specified).
`xlim` | range of abscissa values, used if `x == NULL`. By default, xlim taken as mean plus/minus 3 standard deviations of the normal mixture.
`n` | number of abscissa values to generate if `x` is not specified.
`xy.return` | logical indicating if the result should be a list or just a numeric vector, see below.

### Value

It depends on `xy.return`. If it's false, a numeric vector of the same length as `x`, if true (as per default), a list that can be plotted, with components

`x` | abscissa values corresponding to argument `x`.
`y` | corresponding values r(x).
`f0` | values of the moment matching normal density f0(x).

### Note

The ratio function is used in certain semi-parametric density estimation methods (and theory).

### Examples

      d3 <- norMix(m = 5*(0:2), w = c(0.6, 0.3, 0.1))
      plot(d3)
      rd3 <- r.norMix(d3)
      str(rd3)
      stopifnot(rd3 $ y  == r.norMix(d3, xy.ret = FALSE))
      par(new = TRUE)
      plot(rd3, type = "l", col = 3, axes = FALSE, xlab = "", ylab="")
      axis(4, col.axis=3)

[Package nor1mix version 1.2-3 Index]