Measurement error (i.e. the complement of reliability) results in a downward bias
of observed effect sizes. This attenuation can be emulated by this function.

`attenuate.d(d, reliability)`

## Arguments

- d
The value of Cohen's d (that would be obtained with perfect measurements)

- reliability
The reliability of the measurements of the continuous variable

## Value

The attenuated value of Cohen's d

## References

Bobko, P., Roth, P. L., & Bobko, C. (2001). Correcting
the Effect Size of d for Range Restriction and Unreliability.
*Organizational Research Methods, 4*(1), 46–61.
doi:10.1177/109442810141003

## Author

Gjalt-Jorn Peters & Stefan Gruijters

## Examples

```
attenuate.d(.5, .8);
#> [1] 0.4472136
```