A researcher tested a treatment and a control group in an experiment with 15 subjects in each group.Although a t-test indicated the means for the dependent variable were not statistically different,the effect size for the independent variable was .50.A power analysis revealed that the power of the study was .26.This means that
A) the difference between means in the experiment was .26.
B) the value of the t-statistic is 0.13 (.50 * .26).
C) a statistically significant outcome would be obtained in approximately 1 in 4 attempts with this sample size and effect size.
D) the probability of obtaining a statistically significant difference for this experiment is .74 (1 - .26).

Question

Quizplus · Accepted Answer

A power of .26 means that there is only a 26% chance of finding a statistically significant difference between the groups, even if one exists. This suggests that the study may not have had enough power (i.e. large enough sample size) to detect the effect size of .50. The answer choices A, B, and D are not accurate based on the information provided.

A Researcher Tested a Treatment and a Control Group in an Experiment