plot.profile.nls {nls} | R Documentation |

## Plot a profile.nls Object

### Description

Displays a series of plots of the profile t function and interpolated
confidence intervals for the parameters in a nonlinear regression
model that has been fit with `nls`

and profiled with
`profile.nls`

.

### Usage

## S3 method for class 'profile.nls':
plot(x, levels, conf= c(99, 95, 90, 80, 50)/100,
nseg = 50, absVal =TRUE, ...)

### Arguments

`x` |
an object of class `"profile.nls"` |

`levels` |
levels, on the scale of the absolute value of a t
statistic, at which to interpolate intervals. Usually `conf`
is used instead of giving `levels` explicitly. |

`conf` |
a numeric vector of confidence levels for profile-based
confidence intervals on the parameters. Defaults to ```
c(0.99,
0.95, 0.90, 0.80, 0.50).
``` |

`nseg` |
an integer value giving the number of segments to use in
the spline interpolation of the profile t curves. Defaults to 50. |

`absVal` |
a logical value indicating whether or not the plots
should be on the scale of the absolute value of the profile t.
Defaults to `TRUE` . |

`...` |
other arguments to the `plot` function can be passed here. |

### Author(s)

Douglas M. Bates and Saikat DebRoy

### References

Bates, D.M. and Watts, D.G. (1988),
*Nonlinear Regression Analysis and Its Applications*,
Wiley (chapter 6)

### See Also

`nls`

,
`profile`

,
`profile.nls`

### Examples

data( BOD )
# obtain the fitted object
fm1 <- nls(demand ~ SSasympOrig( Time, A, lrc ), data = BOD)
# get the profile for the fitted model
pr1 <- profile( fm1 )
opar <- par(mfrow = c(2,2), oma = c(1.1, 0, 1.1, 0), las = 1)
plot(pr1, conf = c(95, 90, 80, 50)/100)
plot(pr1, conf = c(95, 90, 80, 50)/100, absVal = FALSE)
mtext("Confidence intervals based on the profile sum of squares",
side = 3, outer = TRUE)
mtext("BOD data - confidence levels of 50%, 80%, 90% and 95%",
side = 1, outer = TRUE)
par(opar)