can be used to [prune](https://en.wikipedia.org/wiki/Decision_tree_pruning) the tree to a lesser number of splits and removes unnecessary information. 

Breiman et al's book [Classification and Regression Trees (1984)](https://www.amazon.com/Classification-Regression-Wadsworth-Statistics-Probability/dp/0412048418) is a must read for learning more about decision trees. 

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# Decision trees

.center[![](slides_img/dt.jpg)]

### Open "4-decision-trees.Rmd" to work through the decision tree examples. 

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