Statistical analysis of transformations leading to normal distribution of measurements of the peripheral glomerular basement membrane

SUMMARY In a morphometric study of the peripheral glomerular basement membrane distribution curves of true membrane thickness were obtained. The measurements were made on photomontages of total glomerular cross‐sections. The distributions were always markedly right‐skewed. A transformation leading to normal distributions was sought. Transformation of basement membrane thickness T to was found to be optimal. The arithmetic mean, T h , of this reciprocal transformation was applied in the statistical analysis of the very earliest stages of diabetic glomerulopathy. It is also meaningful as regards the physiological role of the basement membrane as a filtration barrier.