In a classical experiment carried out from 1918 to 1934, apple trees of different rootstocks were compared. The data for eight tree from each of six rootstocks

trunk girth at 4 years (mm X 100) extension growth at 4 years trunk girth at 15 years (mm X 100) weight of tree above ground at 15 years (1b X 100) Principal Varimax Component Rotated Loadings Loadings Variables f1 f2 f1 f2 Communalities, h. y1 0.787 0.575 0.167 0.960 0.949 y2 0.849 0.467 0.287 0.925 0.939 y3 0.875 -0.455 0.946 0.280 0.973 y4 0.824 -0.547 0.973 0.179 0.978 Variance accounted for 2.785 1.054 1.935 1.903 3.839 Proportion of total variance 0.696 0.264 0.484 0.476 0.960 Cumulative proportion 0.696 0.960 0.484 0.960 0.960