When statisticians talk about effect size, they are referring to
A) the p value obtained from a test such as a t test
B) the difference between the mean of the population the sample is from and the mean of the null hypothesis population
C) whether an$\alpha$level of .05 or .01 was used
D) whether or not the test statistic was in the rejection region.

Question

Quizplus · Accepted Answer

Effect size refers to the magnitude of the difference between groups or the strength of a relationship between variables, not just the statistical significance of the finding. It is often measured as the difference between the mean of the population from which the sample is drawn and the mean of the population under the null hypothesis, among other ways.

When Statisticians Talk About Effect Size, They Are Referring to α\alphaα

When Statisticians Talk About Effect Size, They Are Referring to $\alpha$