120 likes | 212 Views
More Effect Sizes. Handy summary PMA p.72. Single Variable Effect Sizes. Use for central tendency E.g., what is the graduation rate from college? What is the time to complete college? What is the proportion of female college graduates?. Proportion (Direct).
E N D
More Effect Sizes Handy summary PMA p.72
Single Variable Effect Sizes • Use for central tendency • E.g., what is the graduation rate from college? • What is the time to complete college? • What is the proportion of female college graduates?
Proportion (Direct) ES = Effect size. P is the proportion of things of interest. e.g., proportion field goals made from less than 40 yards.
Proportion (Logit) Logit has nice statistical properties.
Aritmethic Mean e.g., mean achievement test score.
Mean Gain (Unstandardized) Before and after comparison or maturation over time. Only used when measures are the same across studies.
Mean Gain (Standardized) Sp is the pooled Standard deviation. G-bar is the mean of the difference (gain) scores, and Sg is the SD of the difference (gain) scores. This is a dependent t for repeated measures. The correlation (r) is between scores pre and post. Used with congeneric measures across studies.
Mean Difference (Unstandardized) Used ONLY if measures are the same across all studies (e.g., used the Beck to study the effectiveness of a treatment for depression (experimental vs. control group design).
Mean Difference(Standardized) Bias correction:
Correlation (Pearson’s r) The statistic and effect size are the same. Fisher’s r to z transformation.