Compound Symmetry Correlation Structure

Usage

corCompSymm(value, form)

Arguments

value the correlation between any two correlated observations. Defaults to 0.
form a one sided formula of the form ~ t, or code{~ t | g}, specifying a time covariate t and, optionally, a grouping factor g. When a grouping factor is present in form, the correlation structure is assumed to apply only to observations within the same grouping level; observations with different grouping levels are assumed to be uncorrelated. Defaults to ~ 1, which corresponds to using the order of the observations in the data as a covariate, and no groups.

Description

This function is a constructor for the corCompSymm class, representing a compound symmetry structure corresponding to uniform correlation. Objects created using this constructor need to be later initialized using the appropriate initialize method.

Value

an object of class corCompSymm, representing a compound symmetry correlation structure.

Author(s)

Jose Pinheiro and Douglas Bates

References

Milliken, G. A. and Johnson, D. E. (1992) "Analysis of Messy Data, Volume I: Designed Experiments", Van Nostrand Reinhold.

See Also

initialize.corStruct

Examples

library(lme)
## covariate is observation order and grouping factor is Subject
cs1 <- corCompSymm(0.5, form = ~ 1 | Subject)


[Package Contents]