The correct formula for effect size using Cohen's d for a paired-samples t test is:
A) (M - $\mu $)/s + $\sigma $.
B) (M - $\mu $)/s.
C) (X - $\mu $)/s.
D) ($\sigma $ - $\mu $)/s.

Question

The correct formula for effect size using Cohen's d for a paired-samples t test is:
A) (M - $\mu  $)/s + $\sigma  $.
B) (M - $\mu  $)/s.
C) (X - $\mu  $)/s.
D) ($\sigma  $ - $\mu  $)/s.

Quizplus · Accepted Answer

The correct formula for effect size using Cohen's d for a paired-samples t test is (M - μ) / s, where M is the mean difference between the paired samples, μ is the population mean difference (which is typically assumed to be zero), and s is the standard deviation of the differences. Option A includes an unnecessary term (F1F1F1S1F1F1F10) and an incorrect sign (+ instead of -). Option C uses X instead of M, which is not the conventional symbol for the mean difference. Option D includes the population standard deviation (σ) instead of the population mean difference (μ).

The Correct Formula for Effect Size Using Cohen's D for a Paired-Samples