Author(s)

Yngvar Reichelt¹, Karl L. Reichelt²

¹Department of Mathematics, University of Oslo, Oslo, Norway.
²Lab 1, No 1337, Sandvika, Norway and Kleve 4541 m, University of Oslo, Oslo, Norway.

Double blind tests of drugs and procedures depend on obtaining two equal and randomly assigned groups to be compared. With a diagnosis based only on symptoms, but with different etiologies, this is not very likely. We here show the probability of obtaining two equal groups with one diagnosis but three etiologies. The mathematical name for such a problem is multivariate hypergeometric distribution. We find that increasing the group size decreases the probability.

Diagnosis, Difference, Etiologies, Distribution, Groups

Reichelt, Y. and Reichelt, K. (2015) Problems with Double Blind in Medicine. Open Journal of Psychiatry, 5, 204-206. doi: 10.4236/ojpsych.2015.52024.