Book Image

Learning Predictive Analytics with Python

By : Ashish Kumar, Gary Dougan
Book Image

Learning Predictive Analytics with Python

By: Ashish Kumar, Gary Dougan

Overview of this book

Social Media and the Internet of Things have resulted in an avalanche of data. Data is powerful but not in its raw form - It needs to be processed and modeled, and Python is one of the most robust tools out there to do so. It has an array of packages for predictive modeling and a suite of IDEs to choose from. Learning to predict who would win, lose, buy, lie, or die with Python is an indispensable skill set to have in this data age. This book is your guide to getting started with Predictive Analytics using Python. You will see how to process data and make predictive models from it. We balance both statistical and mathematical concepts, and implement them in Python using libraries such as pandas, scikit-learn, and numpy. You’ll start by getting an understanding of the basics of predictive modeling, then you will see how to cleanse your data of impurities and get it ready it for predictive modeling. You will also learn more about the best predictive modeling algorithms such as Linear Regression, Decision Trees, and Logistic Regression. Finally, you will see the best practices in predictive modeling, as well as the different applications of predictive modeling in the modern world.
Table of Contents (19 chapters)
Learning Predictive Analytics with Python
Credits
Foreword
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
A List of Links
Index

Chi-square tests


The chi-square test is a statistical test commonly used to compare observed data with the expected data assuming that the data follows a certain hypothesis. In a sense, this is also a hypothesis test. You assume one hypothesis, which your data will follow and calculate the expected data according to that hypothesis. You already have the observed data. You calculate the deviation between the observed and expected data using the statistics defined in the following formula:

Where O is the observed value and E is the expected value while the summation is over all the data points.

The chi-square test can be used to do the following things:

  • Show a causal relationship or independence between one input and output variable. We assume that they are independent and calculate the expected values. Then we calculate the chi-square value. If the null hypothesis is rejected, it suggests a relationship between the two variables. The relationship is not just by chance but statistically proven...