Offering FREE Online Parapsychology Education for the EXCEPTIONAL

Critical Ratio of Difference

Critical Ratio of Difference (CR.sub.d): A critical ratio used to decide whether the numbers of hits obtained under two conditions (or by two groups of subjects) differ significantly from each other; it is obtained by dividing the difference between the two total-hits scores by the standard deviation of the difference.


  1. Parapsychology by Michael A. Thalbourne, Republished by Puente Publications, Charlottesville, VA, USA, 2003