Shade {DescTools} | R Documentation |

## Produce a Shaded Curve

### Description

Sometimes the area under a density curve has to be color shaded, for instance to illustrate a p-value or a specific region under the normal curve.
This function draws a curve corresponding to a function over the interval `[from, to]`

. It can plot also an expression in the variable `xname`

, default `x`

.

### Usage

```
Shade(expr, col = par("fg"), breaks, density = 10, n = 101, xname = "x", ...)
```

### Arguments

`expr` |
the name of a function, or a |

`col` |
color to fill or shade the shape with. The default is taken from |

`breaks` |
numeric, a vector giving the breakpoints between the distinct areas to be shaded differently. Should be finite as there are no plots with infinite limits. |

`density` |
the density of the lines as needed in polygon. |

`n` |
integer; the number of x values at which to evaluate. Default is 101. |

`xname` |
character string giving the name to be used for the x axis. |

`...` |
the dots are passed on to |

### Details

Useful for shading the area under a curve as often needed for explaining significance tests.

### Value

A list with components `x`

and `y`

of the points that were drawn is returned invisibly.

### Author(s)

Andri Signorell <andri@signorell.net>

### See Also

### Examples

```
curve(dt(x, df=5), xlim=c(-6,6),
main=paste("Student t-Distribution Probability Density Function, df = ", 5, ")", sep=""),
type="n", las=1, ylab="probability", xlab="t")
Shade(dt(x, df=5), breaks=c(-6, qt(0.025, df=5), qt(0.975, df=5), 6),
col=c(DescTools::hred, DescTools::hblue), density=c(20, 7))
```

*DescTools*version 0.99.55 Index]