Which of the following is a common measure of effect size?Question 2Answera.Mean deviationb.Cohen's dc.Z-scored.Standard Error

The common measure of effect size among the options provided is Cohen's d.

Here's a step-by-step explanation:

1. Mean deviation: This is a measure of variability in a data set, not effect size. It calculates the average difference between each data point and the mean.

2. Cohen's d: This is a measure of effect size used to indicate the standardized difference between two means. It's often used in psychology and social science research.

3. Z-score: This is a statistical measurement that describes a value's relationship to the mean of a group of values. It is measured in terms of standard deviations from the mean. While it can be related to effect size, it's not a measure of effect size itself.

4. Standard Error: This is a statistical term that measures the accuracy with which a sample distribution represents a population by using standard deviation. However, it's not a measure of effect size.

So, the correct answer is Cohen's d.