Statistical methods find wide application in geology, especially in the study of textures and composition of sedimentary rocks. Certain apparent irregularities in the data, such as highly skewed distributions, use of weight instead of number frequencies, use of unequal class intervals, and some others, required development of special methods of statistical analysis. In part, logarithmic transformations permitted application of conventional methods to the data. Some sedimentary attributes approach Gaussian distributions with no complicating factors. Mineral composition data are commonly binomial or Poisson distributions. Analysis of variance and experimental design are becoming increasingly important in further analysis of geological data.