Description Usage Arguments Details Value Author(s) References Examples
This function can be used to perform a default Bayesian hypothesis test for partial correlation, using a Jeffreys-Zellner-Siow prior set-up (Liang et al., 2008).
1 2 | jzs_partcor(V1, V2, control, alternative = c("two.sided", "less", "greater"),
n.iter=10000,n.burnin=500,standardize=TRUE)
|
V1 |
a numeric vector. |
V2 |
a numeric vector of the same length as V1. |
control |
a numeric vector of the same length as V1 and V2. This variable is partialled out of the correlation between V1 and V2. |
alternative |
specify the alternative hypothesis for the correlation coefficient: |
n.iter |
number of total iterations per chain (see the package |
n.burnin |
length of burn in, i.e. number of iterations to discard at the beginning(see the package |
standardize |
logical. Should the variables be standardized? Defaults to TRUE. |
See Wetzels & Wagenmakers, 2012.
The function returns a list with the following items:
PartCoef |
Mean of the posterior samples of the unstandardized partial correlation (the regression coefficient beta in the equation V2 = intercept + alpha*control + beta*V1). |
BayesFactor |
The Bayes factor for the existence of a partial correlation between V1 and V2, controlled for the control variable. A value greater than one indicates evidence in favor of partial correlation, a value smaller than one indicates evidence against partial correlation. |
PosteriorProbability |
The posterior probability for the existence of a partial correlation between V1 and V2, controlled for the control variable. |
beta |
The posterior samples for the regression coefficient beta. This is the unstandardized partial correlation. |
jagssamples |
The JAGS output for the MCMC estimation of the path. This object can be used to construct a traceplot. |
Michele B. Nuijten <m.b.nuijten@uvt.nl>, Ruud Wetzels, Dora Matzke, Conor V. Dolan, and Eric-Jan Wagenmakers.
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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | ## Not run:
# simulate partially correlated data
X <- rnorm(50,0,1)
C <- .5*X + rnorm(50,0,1)
Y <- .3*X + .6*C + rnorm(50,0,1)
# run jzs_partcor
res <- jzs_partcor(X,Y,C)
# plot posterior samples
plot(res$beta_samples)
# plot traceplot
plot(res$jagssamples)
# where the first chain (theta[1]) is for tau' and the second chain (theta[2]) for beta
## End(Not run)
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