Fig. 4From: Detection of 6-monoacetylemorphine in hair sample of heroin addicts using gas chromatography–mass spectrometry and significance of rehabilitation programMann–Whitney U statistics, frequency distribution for 6-MAM concentration in random heroin addicts’ group and addicts going through rehabilitation at the de-addiction center group. There is a significant difference between mean rank for addicts undergoing rehabilitation compared to random regular addicts for 6-MAM levels in the hair sampleBack to article page