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Profile Likelihood Confidence Interval for Intraclass Correlation

Source: R/profile.R
prof_ci_icc.Rd

Compute confidence intervals for the intraclass correlation of a model fit of class merMod-class.

Usage

prof_ci_icc(x, level = 0.95, eps_max = 1e+06)

Arguments

x

A fitted merMod object from lmer.

level

Confidence level between 0 and 1. Default is .95.

eps_max

The maximum value that the upper limit can be. Default is 1e6.

Value

A named numeric vector with two values showing the lower and upper limit of the intraclass correlation.

Details

This function uses the uniroot function and determine the lower and upper limit by evaluating the profile deviance (for ML) or the -2 profile REML criterion. It works by obtaining the interval for \(\theta = \tau / \sigma\) and transforming the two limits.

The resulting interval is bounded by zero for its lower limit.