Andrews Plots of Iris Data. Fisher iris data are 4-D, and Andrews plots can be used to explore clustering of the three species (Setosa, Versicolor, and Virginica). Discuss the output from the code below.
Cork Boring Data. Cork is the bark of the cork oak (Quercus suber L), a noble tree with very special characteristics that grows in the Mediterranean. This natural tissue has unique qualities: light weight, elasticity, insulation and impermeability, fire retardancy, resistance to abrasion, etc. The data measuring cork boring of trees given in Rao (1948) consist of the weights (in centigrams) of cork boring in four directions (north, east, south, and west) for 28 trees. Data given in can also be found in
(a) Graphically display the data as a data plot, pairwise scatterplots, Andrews plot, and Chernoff faces.
(b) Find the mean x and covariance matrix S for this data set. Find the trace and determinant of S.
(c) Find the Mahalanobis transformation for these data. Check that the covariance matrix for the transformed data is identity.