granova (1.2)

Graphical Analysis of Variance.

This small collection of functions provides distinctive graphics for display of anova results. The two principal functions are granova.1w (a graphic for one way anova) and granova.2w (a corresponding graphic for two way anova). These functions were written to display data for any number of groups, regardless of their sizes (however, very large data sets or numbers of groups are likely to be problematic). For these two functions a specialized approach is used to construct data-based contrast vectors with respect to which anova data are displayed. The result is that the graphics use straight lines, and flat surfaces, to help ensure clear interpretations while being faithful to the standard effect tests in anova; the graphic results are complementary to standard summary tables for these two basic kinds of analysis of variance. Two additional functions are granova.ds (for comparing two dependent samples of data), and granova.contr (which provides graphic displays for a priori contrasts). All functions provide relevant numerical results to supplement the graphic displays of anova data. The graphics based on these functions are aimed at students and non-statistician analysts; but they can be generally helpful for identifying outliers, clusters, trends or the role of non-linear transformations of data. In the case of granova.1w and granova.ds especially, several arguments have been provided to facilitate construction of graphics that accommodate diverse features of data, and their corresponding display requirements.

Maintainer: James E. Helmreich
Author(s): Robert M. Pruzek <> and James E. Helmreich <>

License: GPL (version 2 or later)

Uses: DAAG, car, mgcv, rgl

Released over 11 years ago.