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Applications
Regression Analysis : A simple regression analysis has R^{2} = 0.30.For a simple regression, the effect size is f^{2}= R^{2}/ (1 R^{2}). Thus, the effect size is f^{2}=0.43
ttest: Independent samples ttest showed that the scores of phonics class with N=25 ;Mean=85.04;SD=5.49 and the whole language class with N=25;M=81.16;SD=6.96 differed significantly (t=2.19,p<.05) with the phonics class having better scores. The effect size was 0.63.
Steps for Manipulation
The following are the procedures of some statistical test given as examples :
1. Mean and Standard Deviation (pooled or standard ):
What is the mean of the experimental or followup group?
What is the mean of the comparison or baseline group?
Do these two groups have the same variance?
If yes, used the pooled standard deviation . If no, use the comparison or baseline group standard deviation.If you are not sure and have both, use the comparison or baseline version.
Given the above step, what is the standard deviation.
Calculate "observed" effect size.
ES(effect size)={(Mean exp/post)  (Mean comparison/pre) } / (Std. Dev. Pooled) Or, ES={(Mean exp/post)  (Mean comparison/pre) } / (Std. Dev. Comparison/pre)
ChiSquare
What is the Chisquare
What is the number of observations (n)
Compute "observed" effect size
ES = SQRT((4*(chisquare))/(n(chisquare)))
Our Help
You will be assisted by our statisticians to perform the task of calculating the effect size needed in your dissertation. We will help you to understand what statistical test will be appropriate for your research study.
