Information Technology Reference
In-Depth Information
Figure 9.5
Generalized biplot ordination with CLPs (green spheres) in R .
The CLPs are found in a similar manner by using the pseudo-samples (172,
τ
),
(171,
τ
), (175,
τ
), (168,
τ
)where
τ
takes the 'values' blue , brown and green .TheCLPs
are represented in R in Figure 9.5.
Since the PCO is already referred to its principal axes, the biplot representation in,
say, r = 2 dimensions is simply obtained from the first two dimensions of Figure 9.5,
as shown in Figures 9.6 and 9.7. Figure 9.7 shows the interpolation biplot axis for
the continuous variable height and the associated CLPs for the categorical variable
eye colour .
9.5 The basic points
From (9.10) we may compute the markers for all values, quantitative and categorical,
occurring in X . These are not of great interest for quantitative variables, but they give
all the CLPs for categorical variables. From (9.10) we see that the basic points for the
k th variable are given by (since 1 Y = 0 )
Z k
= 1 Y D k ( I 11 / n ) = 1 Y ( I 11 / n ) D k ( I 11 / n ) ,
Search WWH ::




Custom Search