jzs_cor: A default Bayesian hypothesis test for correlation (Wetzels,... In BayesMed: Default Bayesian Hypothesis Tests for Correlation, Partial Correlation, and Mediation

Description

This function can be used to perform a default Bayesian hypothesis test for correlation, using a Jeffreys-Zellner-Siow prior set-up (Liang et al., 2008).

Usage

 ```1 2 3``` ```jzs_cor(V1, V2, alternative = c("two.sided", "less", "greater"), n.iter=10000,n.burnin=500,standardize=TRUE) ```

Arguments

 `V1` a numeric vector. `V2` a numeric vector of the same length as V1. `alternative` specify the alternative hypothesis for the correlation coefficient: `two.sided`, `greater` than zero, or `less` than zero. `n.iter` number of total iterations per chain (see the package `R2jags`). Defaults to 10000. `n.burnin` length of burn in, i.e. number of iterations to discard at the beginning(see the package `R2jags`). Defaults to 500. `standardize` logical. Should the variables be standardized? Defaults to TRUE.

Details

See Wetzels & Wagenmakers (2012).

Value

The function returns a list with the following items:

 `Correlation` The correlation coefficient for the relation between V1 and V2. The correlation coefficient is calculated by standardizing the mean of the posterior samples: mean(samples)*(sd(V1)/sd(V2)). `BayesFactor` The Bayes factor for the correlation coefficient. A value greater than one indicates evidence in favor of correlation, a value smaller than one indicates evidence against correlation. `PosteriorProbability` The posterior probability for the existence of a correlation between V1 and V2. `alpha` The posterior samples for the correlation coefficient alpha. `jagssamples` The JAGS output for the MCMC estimation of the path. This object can be used to construct a traceplot.

Author(s)

Michele B. Nuijten <m.b.nuijten@uvt.nl>, Ruud Wetzels, Dora Matzke, Conor V. Dolan, and Eric-Jan Wagenmakers.

References

Liang, F., Paulo, R., Molina, G., Clyde, M. A., & Berger, J. O. (2008). Mixtures of g priors for Bayesian variable selection. Journal of the American Statistical Association, 103(481), 410-423.

Nuijten, M. B., Wetzels, R., Matzke, D., Dolan, C. V., & Wagenmakers, E.-J. (2014). A default Bayesian hypothesis test for mediation. Behavior Research Methods. doi: 10.3758/s13428-014-0470-2

Wetzels, R., & Wagenmakers, E.-J. (2012). A Default Bayesian Hypothesis Test for Correlations and Partial Correlations. Psychonomic Bulletin & Review, 19, 1057-1064.

See Also

`jzs_partcor`, `jzs_med`

Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16``` ```## Not run: # generate correlational data X <- rnorm(100) Y <- .4*X + rnorm(100,0,1) # run jzs_cor result <- jzs_cor(X,Y) # inspect posterior distribution plot(result\$alpha_samples) # print a traceplot of the chains plot(result\$jagssamples) ## End(Not run) ```

BayesMed documentation built on May 2, 2019, 9:27 a.m.