So i'm working on a Greenhouse-Geisser correction and i found this "John, Nagao & Sugiura’s test for sphericity" in this publication (https://www.utdallas.edu/~herve/abdi-GreenhouseGeisser2010-pretty.pdf).
Could it be that they calculated the value of the chi square distribution wrong? After Equation 20 they calculate the probability p=0.004, but when i use scipy, i get p=0.0004. So i'm confused if i did not understand the process right or if there is an error(my guess).