Why should we perform an effect size equation for our data?

a)it does not include the n, and so it gives a true idea of how large the variance is between the group means

b)it includes the n, and so it gives a true idea of how large the variance is between the group means

c)it does not include the n and so it gives a true idea of how large the difference is between the group means

d)it includes the n, and so it gives a true idea of how large the difference is between the group means