lizards

datasets

Estimation and inference from generalized linear models based on various methods for bias reduction and maximum penalized likelihood with powers of the Jeffreys prior as penalty. The 'brglmFit' fitting method can achieve reduction of estimation bias by solving either the mean bias-reducing adjusted score equations in Firth (1993) <doi:10.1093/biomet/80.1.27> and Kosmidis and Firth (2009) <doi:10.1093/biomet/asp055>, or the median bias-reduction adjusted score equations in Kenne et al. (2017) <doi:10.1093/biomet/asx046>, or through the direct subtraction of an estimate of the bias of the maximum likelihood estimator from the maximum likelihood estimates as in Cordeiro and McCullagh (1991) <https://www.jstor.org/stable/2345592>. See Kosmidis et al (2020) <doi:10.1007/s11222-019-09860-6> for more details. Estimation in all cases takes place via a quasi Fisher scoring algorithm, and S3 methods for the construction of of confidence intervals for the reduced-bias estimates are provided. In the special case of generalized linear models for binomial and multinomial responses (both ordinal and nominal), the adjusted score approaches to mean and media bias reduction have been found to return estimates with improved frequentist properties, that are also always finite, even in cases where the maximum likelihood estimates are infinite (e.g. complete and quasi-complete separation; see Kosmidis and Firth, 2020 <doi:10.1093/biomet/asaa052>, for a proof for mean bias reduction in logistic regression).

Ioannis Kosmidis

brglm2

Bias Reduction in Generalized Linear Models

Kjell Konis

Nicola Sartori

lizards function

A data frame with 23 rows and 6 columns:<ul>
<li><code>grahami</code>. count of grahami lizards</li>
<li><code>opalinus</code>. count of opalinus lizards</li>
<li><code>height</code>. a factor with levels <code>&lt;5ft</code>, <code>&gt;=5ft</code></li>
<li><code>diameter</code>. a factor with levels <code>&lt;=2in</code>, <code>&gt;2in</code></li>
<li><code>light</code>. a factor with levels <code>sunny</code>, <code>shady</code></li>
<li><code>time</code>. a factor with levels <code>early</code>, <code>midday</code>, <code>late</code></li>
</ul>The variables <code>grahami</code> and <code>opalinus</code> are counts of two lizard
species at two different perch heights, two different perch
diameters, in sun and in shade, at three times of day.

Format

Habitat preferences of lizards — lizards

A data frame with 23 rows and 6 columns:<ul>
<li><code>grahami</code>. count of grahami lizards</li>
<li><code>opalinus</code>. count of opalinus lizards</li>
<li><code>height</code>. a factor with levels <code>&lt;5ft</code>, <code>&gt;=5ft</code></li>
<li><code>diameter</code>. a factor with levels <code>&lt;=2in</code>, <code>&gt;2in</code></li>
<li><code>light</code>. a factor with levels <code>sunny</code>, <code>shady</code></li>
<li><code>time</code>. a factor with levels <code>early</code>, <code>midday</code>, <code>late</code></li>
</ul>

The variables <code>grahami</code> and <code>opalinus</code> are counts of two lizard
species at two different perch heights, two different perch
diameters, in sun and in shade, at three times of day.

lizards: Habitat preferences of lizards

Description

Usage

Arguments

Format

See Also