Assume you are doing a correlation study between two brain areas, A and B. For each subject, you get a single value, the correlation between A and B. And you have 100 subjects.
How do you know if the mean of the correlation is significantly different from 0? And how do you perform statistic tests on these correlation values?
Prior to do the statistics on correlation value, you need to convert them to something which is more “normally” behaved. Fisher’s transformation will do the work:
