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Machine Learning with R Quick Start Guide

You're reading from   Machine Learning with R Quick Start Guide A beginner's guide to implementing machine learning techniques from scratch using R 3.5

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Product type Paperback
Published in Mar 2019
Publisher Packt
ISBN-13 9781838644338
Length 250 pages
Edition 1st Edition
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Author (1):
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Iván Pastor Sanz Iván Pastor Sanz
Author Profile Icon Iván Pastor Sanz
Iván Pastor Sanz
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Toc

Testing a random forest model

A random forest is an ensemble of decision trees. In a decision tree, the training sample, which is based on the independent variables, will be split into two or more homogeneous sets. This algorithm deals with both categorical and continuous variables. The best attribute is selected using a recursive selection method and is split to form the leaf nodes. This continues until a criterion that's meant to stop the loop is met. Every tree that's created by the expansion of leaf nodes is considered to be a weak learner. This weak learner is built on top of the rows and columns of the subsets. The higher the number of trees, the lower the variance. Both classification and regression random forests calculate the average prediction of all of the trees to make a final prediction.

When a random forest is trained, some different parameters can be set...

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