# BFF

Bayes Factor Functions

This package provides the Bayes Factor values for different effect
sizes from 0 to 1. A small effect size is usually considered from 0.2 to
0.5, medium effect sizes from 0.5 to 0.8, and large effect sizes as
greater than 0.8.

Using this package is very similar to using the familiar t, z, chi^2,
and F tests in R. You will need the same information - the test
statistic, degrees of freedom, and sample size. A graph is produced that
shows the BFF curve over the different effect sizes.

For evaluating evidence from multiple studies (see ‘Bayes factor
functions’, 2023 (arxiv)), the parameter ‘r’ can also be set. The
default value for r is 1, but ‘r’ can be suggested that maximizes the
bayes factor at each tau by setting the ‘maximization’ argument in each
test to “TRUE.”

## Installation

The R package ‘BFF’ is available from CRAN, use the commands below to
install the most recent Github version.

```{r, eval = FALSE} # Plain installation
devtools::install_github(“rshudde/BFF”) # BFF package

```
Example
-------
```{r}
library(BFF)
z_BFF_one = z_test_BFF(z_stat = 2.5, n = 50) #one sample z-test
z_BFF_two = z_test_BFF(z_stat = 2.5, one_sample = FALSE, n1 = 50, n2 = 50) #two sample z-test
plot(z_BFF_two) #to view the plot of BFF vs the maximized omega (here for the two sample z-test)
```