# Finds a Reasonable Domain for Plotting a Graph

### Description

This function computes a reasonable domain for plotting one, two, or three distribution functions by truncating small tail probabilities. This function also lists the population medians.

### Usage

1 2 |

### Arguments

`xmin` |
A lower bound, usually set to |

`xmax` |
An upper bound, usually set to |

`distA` |
Character variable naming the first probability density function (starting with "d") or cumulative density function (starting with "p"). |

`parmA1` |
The first argument in |

`parmA2` |
The second argument in |

`distB` |
Character variable naming the second probability density function (starting with "d") or cumulative density function (starting with "p"). |

`parmB1` |
The first argument in |

`parmB2` |
The second argument in |

`distC` |
Character variable naming the third probability density function (starting with "d") or cumulative density function (starting with "p"). |

`parmC1` |
The first argument in |

`parmC2` |
The second argument in |

### Details

This function `getMinMax`

is automatically called by `plotDist`

and `shadeDist`

,
so the user does not actually need to directly call `getMinMax`

when
executing `plotDist`

and `shadeDist`

.
This function by itself does not construct a graph.

### Value

`xmin` |
A reasonable value of a lower bound for the domain of a graph. |

`xmax` |
A reasonable value of an upper bound for the domain of a graph. |

`medianA` |
The population median of |

`medianB` |
The population median of |

`medianC` |
The population median of |

### Author(s)

Steven T. Garren, James Madison University, Harrisonburg, Virginia, USA

### See Also

`plotDist`

and `shadeDist`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 | ```
getMinMax( , , "dnorm", 20, 5 ) # Normal(mu=20, sigma=5)
# Standard normal, and t with 4 degrees of freedom
getMinMax( , , "dnorm", 0, 1, "dt", 4, 0 )
# Standard normal, central t with 4 d.f., and t with 4 d.f. and non-centrality parmater = 1.2
getMinMax( , , "dnorm", 0, 1, "dt", 4, 0, "dt", 4, 1.2 )
# Force minimum to be -3.
getMinMax( -3, , "dnorm", 0, 1 )
# Force maximum to be 3.
getMinMax( , 3, "dnorm", 0, 1 )
``` |