Correlation Structure

Correlation structures are used to model within-group correlation not captured by the random effects. These are generally associated with temporal or spatial dependencies.

Type The type of correlation structure. The available correlation structures are:

See the online Help for the corresponding corStruct S-PLUS function to determine the specific parameters and covariates for each of the correlation structures.

Time Variable The continuous time covariate for correlation structures AR(1), ARMA(p,q), Continuous AR(1), Compound Symmetric, and General Symmetric.

Spatial Variables The spatial covariate(s) for correlation structures Exponential, Gaussian, Linear, Rational Quadratic, and Spherical.

Group Variable The grouping factor(s). Multiple grouping factors are converted to ordered factors.

Parameters Parameters as needed for the different correlation structures.