Enables a conversion between Probability of Direction (pd) and p-value.

## Usage

```
pd_to_p(pd, ...)
# S3 method for class 'numeric'
pd_to_p(pd, direction = "two-sided", verbose = TRUE, ...)
p_to_pd(p, direction = "two-sided", ...)
convert_p_to_pd(p, direction = "two-sided", ...)
convert_pd_to_p(pd, ...)
```

## Arguments

- pd
A Probability of Direction (pd) value (between 0 and 1). Can also be a data frame with a column named

`pd`

,`p_direction`

, or`PD`

, as returned by`p_direction()`

. In this case, the column is converted to p-values and the new data frame is returned.- ...
Arguments passed to or from other methods.

- direction
What type of p-value is requested or provided. Can be

`"two-sided"`

(default, two tailed) or`"one-sided"`

(one tailed).- verbose
Toggle off warnings.

- p
A p-value.

## Details

Conversion is done using the following equation (see *Makowski et al., 2019*):

When `direction = "two-sided"`

$$p = 2 \times (1 - p_d)$$

When `direction = "one-sided"`

$$p = 1 - p_d$$

Note that this conversion is only valid when the lowest possible values of pd
is 0.5 - i.e., when the posterior represents continuous parameter space (see
`p_direction()`

). If any pd < 0.5 are detected, they are converted to a p
of 1, and a warning is given.

## References

Makowski, D., Ben-Shachar, M. S., Chen, S. H. A., and Lüdecke, D. (2019).
*Indices of Effect Existence and Significance in the Bayesian Framework*.
Frontiers in Psychology 2019;10:2767. doi:10.3389/fpsyg.2019.02767