A researcher reports that the size of an effect in some population is d = 0.88.Which of the following is an appropriate interpretation for d?
A) The effect observed in the population was significant.
B) Mean scores were significant by 0.88 points in the sample.
C) Mean scores were significant by 0.88 points in the population.
D) Mean scores shifted 0.88 standard deviations in the population.

Question

Quizplus · Accepted Answer

The effect size (d = 0.88) represents the standardized mean difference between two groups or conditions. Specifically, it indicates that the mean scores on the outcome variable shifted by 0.88 standard deviations in the population, which is a moderately large effect size. Therefore, option D is the appropriate interpretation. Option A suggests significance, but d alone does not provide information about statistical significance. Option B refers to mean scores in the sample, not the population, and option C repeats this error and suggests significance without providing necessary statistical tests.

A Researcher Reports That the Size of an Effect in Some