Cohen's d with a confidence interval, complementing the TOST verdict

The interval is the (1 - 2 * alpha) confidence interval for the standardised mean difference; for alpha = 0.05 this is the 90% interval that corresponds exactly to a TOST decision at the .05 level (Lakens, 2017). Reporting the interval, rather than only a binary verdict, makes the realised imbalance and its sampling uncertainty explicit, and keeps the dependence on the number of items visible. With few items the interval is wide, so a small point estimate cannot be over-read as evidence of a small true difference (Sassenhagen & Alday, 2016).

Usage

cohens_d_ci(x, y, alpha = 0.05)

Arguments

x, y

Numeric vectors.

alpha

Significance level matching the TOST (default 0.05).

Value

A list with d, ci_low and ci_high.