# Range of a Unimodal Distribution

### Description

Given the parameters of a unimodal distribution and the root of the density function name, this function determines the range outside of which the density function is negligible, to a specified tolerance.

### Usage

1 | ```
distCalcRange(densFn, param = NULL, tol = 10^(-5), ...)
``` |

### Arguments

`densFn` |
Character. The name of the density function for which range calculation is required. |

`tol` |
Tolerance. |

`param` |
Numeric. A vector giving the parameter values for the
distribution specified by |

`...` |
Passes arguments to |

### Details

The name of the unimodal density function must be supplied as the
characters of the root for that density (e.g. `norm`

,
`ghyp`

). The particular unimodal distribution being considered is
specified by the values of the parameters or of the
`param`

vector.

The function gives a range, outside of which
the density is less than the given tolerance. It is used in
determining break points for the separate sections over which
numerical integration is used to determine the distribution
function. The points are found by using `uniroot`

on the
density function.

### Value

A two-component vector giving the lower and upper ends of the range.

### Author(s)

David Scott d.scott@auckland.ac.nz, Joyce Li xli053@aucklanduni.ac.nz

### See Also

`qDist`

### Examples

1 2 3 4 | ```
normRange <- distCalcRange("norm", tol = 10^(-7), mean = 4, sd = 1)
normRange
tRange <- distCalcRange("t", tol = 10^(-5), df = 4)
tRange
``` |