dot-psi_kenward: Modified psi function for test statistic correction

In antedep: Antedependence Models for Longitudinal Data

Modified psi function for test statistic correction

Description

Computes the psi function used in the modified likelihood ratio test (Kenward, 1987) for better small-sample approximation.

Usage

.psi_kenward(x, y)

Arguments

x	First argument.
y	Second argument.

Details

psi(x, y) is defined as:

• 0 if x = 0

• (2y - 1) / (2y(y - 1)) if x = 1

• 2 * sum from l=1 to x/2 of (y + 2l - 2)^(-1) if x > 0 and even

• psi(1, y) + psi(x - 1, y + 1) if x > 1 and odd

Value

Value of psi(x, y).

antedep documentation built on April 25, 2026, 1:06 a.m.