For a study using a t test for independent means, the approximate number of participants needed for 80% power for an estimated large effect size and using a two-tailed test is:
A)26
B)50
C)64
D)310

Question

Quizplus · Accepted Answer

For a large effect size (Cohen's d = 0.8) and 80% power in a two-tailed test, approximately 26 participants are needed according to power analysis tables or software.

For a Study Using a T Test for Independent Means