img/pca-sqload.png"/&gt;
&lt;img style="left;width:350px;" src="slides_img/pca-ml.png"/&gt;

### Open "08-PCA.Rmd" to work through the principal component analysis examples.

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# Hierarchical agglomerative clustering

Hierarchical agglomerative clustering is a bottom-up approach. Each observation begins as its own cluster and forms clusters with like items as it moves up the hierarchy. That is, all leaves are their own clusters to begin with and form clusters as grouping moves up the trunk and various br