Miscellanea. Studies in the history of probability and statistics XLVII. Pizzetti's contributions to the statistical analysis of normally distributed observations, 1891
Anders D. Hald · Biometrika · 2000
Pizzetti's work is considered as bridging the gap between Helmert and Fisher. By means of an orthonormal transformation Pizzetti decomposed the total sum of squares in the linear normal model into its constituent and independent parts, thus providing the theoretical basis for the analysis of variance in the fixed effects model. He calculated a table of the χ2 distribution, which he used for finding probability limits for s/σ. He derived the estimates of the components of variance in the random effects model for the one-way classification.