Effect Size Flashcards
1
Q
Cohen’s rule
A
Effect size measures either measure the sizes of associations or the sizes of differences. You already know the most common effect-size measure, as the correlation/regression coefficients r and R are actually measures of effect size. Because r covers the whole range of relationship strengths, from no relationship whatsoever (zero) to a perfect relationship (1, or -1), it is telling us exactly how large the relationship really is between the variables we’ve studied – and is independent of how many people were tested. Cohen provided rules of thumb for interpreting these effect sizes, suggesting that an r of |.1| represents a ‘small’ effect size, |.3| represents a ‘medium’ effect size and |.5| represents a ‘large’ effect size.
