| qqnorm.lme {nlme} | R Documentation |
Diagnostic plots for assessing the normality of residuals and random
effects in the linear mixed-effects 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 'lme': qqnorm(y, form, abline, id, idLabels, grid, ...)
y |
an object inheriting from class lme, representing
a fitted linear mixed-effects model or from class lmList,
representing a list of lm objects, or from class lm,
representing a fitted linear model, or from class nls,
representing a nonlinear 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,
or a random effects matrix. Default is ~ resid(., type = "p"),
corresponding to a normal plot of the standardized residuals
evaluated at the innermost level of nesting. |
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 is FALSE. |
... |
optional arguments passed to the Trellis plot function. |
a diagnostic Trellis plot for assessing normality of residuals or random effects.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
## Not run: data(Orthodont) fm1 <- lme(distance ~ age, Orthodont, random = ~ age | Subject) # normal plot of standardized residuals by gender qqnorm(fm1, ~ resid(., type = "p") | Sex, abline = c(0, 1)) # normal plots of random effects qqnorm(fm1, ~ranef(.)) ## End(Not run)