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Hands-On Ensemble Learning with R

Hands-On Ensemble Learning with R

By : Tattar
3 (1)
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Hands-On Ensemble Learning with R

Hands-On Ensemble Learning with R

3 (1)
By: Tattar

Overview of this book

Ensemble techniques are used for combining two or more similar or dissimilar machine learning algorithms to create a stronger model. Such a model delivers superior prediction power and can give your datasets a boost in accuracy. Hands-On Ensemble Learning with R begins with the important statistical resampling methods. You will then walk through the central trilogy of ensemble techniques – bagging, random forest, and boosting – then you'll learn how they can be used to provide greater accuracy on large datasets using popular R packages. You will learn how to combine model predictions using different machine learning algorithms to build ensemble models. In addition to this, you will explore how to improve the performance of your ensemble models. By the end of this book, you will have learned how machine learning algorithms can be combined to reduce common problems and build simple efficient ensemble models with the help of real-world examples.
Table of Contents (15 chapters)
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12
12. What's Next?
13
A. Bibliography
14
Index

Stack ensembling

An introductory and motivational example of the stacked regression was provided in Chapter 1, Introduction to Ensemble Techniques. Here, we will continue the discussion of stacked ensembles for a regression problem which has not been previously developed.

With stacked ensembling, the outputs of several weak models are given as an input variable, along with the covariates used to build the earlier models, to build a stack model. The form of the stack model might be one of these, or it can be a different model. Here, we will simply use the eight regression models (used in previous sections) as weak models. The stacking regression model is selected as the gradient boosting model, and it will be given the original input variables and predictions of the new models, as follows:

> SP_lm_train <- predict(SP_lm,newdata=ht_imp)
Warning message:
In predict.lm(SP_lm, newdata = ht_imp) :
  prediction from a rank-deficient fit may be misleading
> SP_rpart2_train <- predict...

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