THESIS

Plots of the clustering statistics (pseudo F, cubic clustering criterion and
pseudo t 2 ) against the member of cluster were obtained using the PROC PLOT
statement. A consensus among these statistics (local peaks of pseudo F and t 2 and
local dips of cubic clustering criterion) was used to determine the number of clusters
to be considered in the analysis. The process that involves the use of these statistics
in determining the right number of cluster is considered to as “stopping point”. The
good stopping points referred to are the local peaks of pseudo F and pseudo t 2 and the
local dips of cubic clustering criterion (Callantes, 2003). Using PROC PLOT
statement, the plots of these statistics against the number of cluster were obtained
(Figure 3 to 5).
II. Nominal traits
The qualitative data listed in Appendix Table A3 was analyzed by R
program version 2.6.1 (Hornik, 2007). The cluster analysis was done the interaction
mode of the software (method = average). The dendrogram showing the stratified
accessions of Solanum spp. based on selected nominal traits was then generated using
the tree plot of the graphics window.
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