posterior_r: Samples from the posterior distribution of the correlation...

View source: R/posterior_distributions.R

posterior_rR Documentation

Samples from the posterior distribution of the correlation coefficient. The posterior distribution is generated using Fisher's fiducial approach and corresponds exactly to the use of a Jeffrey's prior.

Description

Samples from the posterior distribution of the correlation coefficient. The posterior distribution is generated using Fisher's fiducial approach and corresponds exactly to the use of a Jeffrey's prior.

Usage

posterior_r(r, df, filter = 0, upper_null = 0, fixed = FALSE, ndraws = 2e+05)

Arguments

r

The correlation of the previous study.

df

The degrees of freedom in the previous study.

filter

The filter value reflects the probability of nonsignificant results being filtered. filter = 0 means that there is no filtering and you would have observed nonsignificant results. filter = 1 means that only significant results are observed and you would never have seen nonsigificant results if they had occurred. Filtering is based on alpha = .05 and assumes that are have observed a significant result. Filtering is conducted by weighting (actually filtering) the posterior distribution. For instance, if filter = 1, then the posterior of the null (i.e., the noncentrality parameter is 0) is up to 20 times more likely than when the noncentrality parameter is very large. Setting filter > 0 slows estimation.

upper_null

Specifies the upper value of the composite null hypothesis in units of the correlation. The default value of upper_null = 0 keeps the point null hypothesis. A value of, for instance, upper_null = .05 would remove all posterior values between -.05 and .05.

fixed

Specifies whether the predictors in the model are either fixed or random. The default is FALSE for random predictors.

ndraws

Specifies the number of initial samples from the posterior. For small effect sizes and when filter or upper_null > 0 the number of returned samples from the posterior distribution will be lower than ndraws.

Value

A vector of samples from the posterior distribution in units of the correlation parameter ρ.


jbiesanz/fabs documentation built on July 15, 2022, 11:02 p.m.