potthoff {growth}R Documentation

Potthoff and Roy Growth Curve Model

Description

potthoff fits the Potthoff and Roy repeated measurements growth curve model with unstructured covariance matrix to completely balanced data.

Usage

potthoff(response, x, ccov=NULL, times=NULL, torder=0, orthogonal=TRUE)

Arguments

response A matrix or dataframe of response values.
x A matrix defining the complete intersubject differences or a Wilkinson and Rogers formula that will create one.
ccov A matrix of columns of the baseline covariates to be actually fitted, with one row per individual or a W&R formula that will create one.
times A vector of unequally spaced times when they are the same for all individuals. Not necessary if equally spaced.
torder Order of the polynomial in time to be fitted. If non-numeric, the full model in time is fitted.
orthogonal If TRUE, uses orthogonal polynomials for time, otherwise only centres times at their mean.

Value

A list of class potthoff is returned.

Author(s)

J.K. Lindsey

See Also

carma, elliptic, lm.

Examples

y <- matrix(rnorm(40),ncol=5)
x <- gl(2,4)
# full model with treatment effect
potthoff(y, ~x, torder="f", ccov=~x)
# no time trend with treatment effect
potthoff(y, ~x, torder=0, ccov=~x)
# quadratic time with treatment effect
potthoff(y, ~x, torder=2, ccov=~x)
# full model without treatment effect
potthoff(y, ~x, torder="f")
# linear time without treatment effect
potthoff(y, ~x, torder=1)

[Package growth version 1.0 Index]