qqnorm.gls {nlme} | R Documentation |

Diagnostic plots for assessing the normality of residuals the
generalized least squares fit are obtained. The `form`

argument
gives considerable flexibility in the type of plot specification. A
conditioning expression (on the right side of a `|`

operator)
always implies that different panels are used for each level of the
conditioning factor, according to a Trellis display.

## S3 method for class 'gls': qqnorm(y, form, abline, id, idLabels, grid, ...)

`y` |
an object inheriting from class `gls` , representing
a generalized least squares fitted model. |

`form` |
an optional one-sided formula specifying the desired type of
plot. Any variable present in the original data frame used to obtain
`y` can be referenced. In addition, `y` itself
can be referenced in the formula using the symbol
`"."` . Conditional expressions on the right of a `|`
operator can be used to define separate panels in a Trellis
display. The expression on the right hand side of `form` and to
the left of a `|` operator must evaluate to a residuals
vector. Default is `~ resid(., type = "p")` ,
corresponding to a normal plot of the standardized residuals. |

`abline` |
an optional numeric value, or numeric vector of length two. If given as a single value, a horizontal line will be added to the plot at that coordinate; else, if given as a vector, its values are used as the intercept and slope for a line added to the plot. If missing, no lines are added to the plot. |

`id` |
an optional numeric value, or one-sided formula. If given as
a value, it is used as a significance level for a two-sided outlier
test for the standardized residuals (random effects). Observations with
absolute standardized residuals (random effects) greater than the
1 - value/2 quantile of the standard normal distribution are
identified in the plot using `idLabels` . If given as a one-sided
formula, its right hand side must evaluate to a logical, integer, or
character vector which is used to identify observations in the
plot. If missing, no observations are identified. |

`idLabels` |
an optional vector, or one-sided formula. If given as a
vector, it is converted to character and used to label the
observations identified according to `id` . If given as a
one-sided formula, its right hand side must evaluate to a vector
which is converted to character and used to label the identified
observations. Default is the innermost grouping factor. |

`grid` |
an optional logical value indicating whether a grid should
be added to plot. Default depends on the type of Trellis plot used:
if `xyplot` defaults to `TRUE` , else defaults to
`FALSE` . |

`...` |
optional arguments passed to the Trellis plot function. |

a diagnostic Trellis plot for assessing normality of residuals.

Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu

fm1 <- gls(follicles ~ sin(2*pi*Time) + cos(2*pi*Time), Ovary, correlation = corAR1(form = ~ 1 | Mare)) qqnorm(fm1, abline = c(0,1))

[Package *nlme* version 3.1-66 Index]