Distribution of sperm counts in suspected infertile men.
Probit plots of sperm concentration for 1711 suspected infertile men (those with azoospermia being excluded) were compared for the untransformed and loge-, square root- and cube root-transformed values. For the distribution of sperm concentrations, which was highly skewed towards low values, the square-root transformation produced the most normal (Gaussian) distribution. Loge and cube-root transformations caused skewing towards high values. Such treatment of the data should always be considered before using parametric statistical tests to make comparisons between sperm concentrations of groups of men.
D006801:Humans; D007248:Infertility, Male / Q000473:pathology*; D008297:Male; D013076:Sperm Count; D013223:Statistics as Topic