plot_posterior {abtest} R Documentation

## Plot Posterior

### Description

Function for plotting the posterior distribution.

### Usage

```plot_posterior(
x,
what = "logor",
hypothesis = "H1",
ci = 0.95,
p1lab = "p1",
p2lab = "p2",
...
)
```

### Arguments

 `x` object of class `"ab"`. `what` character specifying for which quantity the posterior should be plotted. Either `"logor"` (i.e., log odds ratio) , `"or"` (i.e., odds ratio), `"p1p2"` (i.e., the marginal posteriors of the latent "success" probabilities in the experimental and control condition), `"rrisk"` (i.e., relative risk, the ratio of the "success" probability in the experimental and the control condition), or `"arisk"` (i.e., absolute risk, the difference of the "success" probability in the experimental and control condition). `hypothesis` character specifying whether to plot the two-sided posterior distribution (i.e., "H1"), the one-sided posterior distribution with lower truncation point (i.e., "H+"), or the one-sided posterior distribution with upper truncation point (i.e., "H-"). `ci` numeric value specifying the `ci`% central credible interval. The default is 0.95 which yields a 95% central credible interval. `p1lab` determines p1 x-axis label. Only relevant for ```what = "p1p2"```. `p2lab` determines p2 x-axis label. Only relevant for ```what = "p1p2"```. `p1adj` determines p1 x-axis label adjustment. Only relevant for `what = "p1p2"`. `p2adj` determines p2 x-axis label adjustment. Only relevant for `what = "p1p2"`. `...` further arguments

### Details

The resulting plot displays the posterior density for the quantitiy of interest and also displays the corresponding prior density. The values of the posterior median and a `ci`% central credible interval are displayed on top of the plot.

### Author(s)

Quentin F. Gronau

### Examples

```# synthetic data
data <- list(y1 = 10, n1 = 28, y2 = 14, n2 = 26)

# Bayesian A/B test with default settings
ab <- ab_test(data = data, posterior = TRUE)

# plot parameter posterior
plot_posterior(x = ab, what = "logor")
plot_posterior(x = ab, what = "or")
plot_posterior(x = ab, what = "p1p2")
plot_posterior(x = ab, what = "rrisk")
plot_posterior(x = ab, what = "arisk")

# example of good width and height values for saving to file
cairo_pdf(file.path(tempdir(), "test_plot.pdf"),
width = 530 / 72, height = 400 / 72)
plot_posterior(ab, what = "p1p2")
dev.off()

```

[Package abtest version 1.0.1 Index]