summarybal: Summary of a balanced longitudinal data set

Description

For a balanced longitudinal data set a vector of the mean response and variances at defined time points is returned along with the correlation matrix of the responses across the time points.

Usage

summarybal(object, Y.col, times, use = "all.obs", na.rm, ...)

Value

A list with three elements:

mean.vect: a matrix with the time points in the first column and the mean response vector as the second column.
variance: The vector of variances for the response at the time points.
cor.mtx: Containing the correlation matrix of the responses between each pair of time points.

Arguments

object: a longitudinal data set in the balanced format.
Y.col: the column numbers of the longitudinal measurements at each design time point in the object. This does not have to be all of the longitudinal measurements taken and may be a subset instead.
times: a vector of unique time points of the longitudinal measurements. This does not have to be all of the study time points and may be a subset instead, but should match the columns defined in Y.col.
use: an optional character string giving a method for computing covariances in the presence of missing values. This must be (an abbreviation of) one of the strings "all.obs", "complete.obs" or "pairwise.complete.obs". Defaults to use = "all.obs".
na.rm: logical. Should missing values be removed? By default, na.rm = FALSE.
...: further arguments for the summary.

Author

Ines Sousa

Examples

Run this code

data(mental)
summarybal(mental, Y.col = 2:7, times = c(0, 1, 2, 4, 6, 8), na.rm = TRUE)