Perform a robustness analysis by systematically varying the values of the alternative prior

```
bfrr(
likelihood,
alternative_prior,
null_prior,
parameters,
steps = 100L,
cutoff = 3L,
multicore = TRUE
)
```

- likelihood
`likelihood`

object representing the data- alternative_prior
`prior`

object for the alternative prior- null_prior
`prior`

object for the null prior- parameters
`list`

of min and max values for each parameter to vary over.- steps
`numeric`

the number of steps each parameter is varied over. (Default: 100 steps)- cutoff
Minimum Bayes factor value for evidence for the hypothesis (Default: 3)

- multicore
Run robustness analysis across multiple cores (Default: TRUE if available)

A `robustness`

object

```
# define a likelihood
data_model <- likelihood(family = "normal", mean = 1, sd = 5)
# define the alternative prior
alternative_prior <- prior(family = "normal", mean = 5, sd = 4)
# define the null prior
null_prior <- prior(family = "point", point = 0L)
# set the parameters to vary and the range to vary them across
# vary the mean from -10 to 5
# vary the sd from 1 to 5
parameters <- list(mean = c(-10, 5), sd = c(1, 5))
# mark all Bayes factors larger/smaller than 3/.3 as evidence for the
# alternative / null
cutoff <- 3
bfrr(data_model, alternative_prior, null_prior, parameters, steps = 10,
cutoff,
multicore = FALSE
)
#> Prior robustness analysis:
#>
#> Alternative prior
#> -----------------
#> Family
#> normal
#> Parameters
#> mean: 5
#> sd: 4
#>
#> Null prior
#> -----------------
#> Family
#> point
#> Parameters
#> point: 0
#>
#> Likelihood
#> -----------------
#> Family
#> normal
#> Parameters
#> mean: 1
#> sd: 5
#>
#> The original parameters gave a Bayes factor of 0.66.
#> Using the cutoff value of 3, this result is inconclusive.
#>
#> 2 parameters of the alternative prior were varied for the robutness analysis:
#> The mean was varied from -10 to 5 (step size: 1.5)
#> The sd was varied from 1 to 5 (step size: 0.4)
#>
#> Outcome
#> -----------------
#> 25 of 100 (0.25) tested priors provided evidence for H0 (BF < 0.33)
#>
#> 0 of 100 (0) tested priors provided evidence for H1 (BF > 3)
#>
#> 75 of 100 (0.75) tested priors were inconclusive (0.33 < BF < 3)
#>
#> The conclusion of 'Inconclusive' was robust over 0.75 tested priors
#>
```