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Practical Data Analysis

You're reading from  Practical Data Analysis

Product type Book
Published in Oct 2013
Publisher Packt
ISBN-13 9781783280995
Pages 360 pages
Edition 1st Edition
Languages
Author (1):
Hector Cuesta Hector Cuesta
Profile icon Hector Cuesta
Toc

Table of Contents (24) Chapters close

Practical Data Analysis
Credits
Foreword
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
1. Getting Started 2. Working with Data 3. Data Visualization 4. Text Classification 5. Similarity-based Image Retrieval 6. Simulation of Stock Prices 7. Predicting Gold Prices 8. Working with Support Vector Machines 9. Modeling Infectious Disease with Cellular Automata 10. Working with Social Graphs 11. Sentiment Analysis of Twitter Data 12. Data Processing and Aggregation with MongoDB 13. Working with MapReduce 14. Online Data Analysis with IPython and Wakari Setting Up the Infrastructure Index

Dimensionality reduction


The dimensionality of a model is the number of independent attributes in the dataset. In order to reduce the complexity of the model we need to reduce the dimensionality without sacrificing accuracy. When we work in complex multidimensional data, we need to select the features that can improve the accuracy of the technique that we are using. Sometimes, we don't know if the variables are independent or if they share some kind of relationship. We need some criteria to find the best features and reduce the number of variables under consideration. In order to address these problems, we will perform three techniques: feature selection, feature extraction, and dimension reduction.

  • Feature selection: We will select a subset of features in order to get better training times or improve the model accuracy. In data analysis, finding the best features for our problem is often guided by intuition and we don't know the real value of a variable until we test it. However, we may...

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