I am not the expert in meta-analysis, so any help will be appreciated. I am currently finding some materials but in the meantime a few quick questions.
I know how to combine Z scores to get an overall Z and p level using Stouffer's methods - in my case I have 4 p values, and I would find the one-tail Z corresponding to each p (using a negative Z IF the results were in the opposite direction). Adding the Z values and dividing by square root of the number of studies yields a Z distribution. That I can do. But I have F and p values. F distributions are chi2 ratios, positive, not normal .. etc. What would be the corresponding Z value for a p value greater than .5? It can't be a negative Z. I was toying with using Fisher's method for combining probabilities instead ... -2*Sum log (p) which distributes as Chi square. I found very little info on this method other than it gives similar but not identical results to Stouffer. I played with a few hypothetical numbers and ended up with quite different p values in the end. Is that method still used? In the meantime I will start plowing through a little book by Schultz on meta analysis ... Any help will be appreciated! JK p.s. I can also combine effect sizes across the studies, which I may do later, but, what I really want now is one overall "significance" level for these quadratic trends ... ========================== John W. Kulig, Ph.D. Professor of Psychology Coordinator, University Honors Plymouth State University Plymouth NH 03264 ========================== --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=24268 or send a blank email to leave-24268-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
