pd_to_p: Convert between Probability of Direction (pd) and p-value.
Description
Enables a conversion between Probability of Direction (pd) and p-value.
Usage
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, direction = "two-sided", verbose = TRUE, ...)
Arguments
pd
A Probability of Direction (pd) value (between 0 and 1).
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.
...
Arguments passed to or from other methods.
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. tools:::Rd_expr_doi("10.3389/fpsyg.2019.02767")