Book Image

Statistics for Data Science

Book Image

Statistics for Data Science

Overview of this book

Data science is an ever-evolving field, which is growing in popularity at an exponential rate. Data science includes techniques and theories extracted from the fields of statistics; computer science, and, most importantly, machine learning, databases, data visualization, and so on. This book takes you through an entire journey of statistics, from knowing very little to becoming comfortable in using various statistical methods for data science tasks. It starts off with simple statistics and then move on to statistical methods that are used in data science algorithms. The R programs for statistical computation are clearly explained along with logic. You will come across various mathematical concepts, such as variance, standard deviation, probability, matrix calculations, and more. You will learn only what is required to implement statistics in data science tasks such as data cleaning, mining, and analysis. You will learn the statistical techniques required to perform tasks such as linear regression, regularization, model assessment, boosting, SVMs, and working with neural networks. By the end of the book, you will be comfortable with performing various statistical computations for data science programmatically.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Transformations


A thought-provoking type of data cleaning, which may be a new concept for a data developer, is data transformation. Data transformation is a process where the data scientist actually changes what you might expect to be valid data values through some mathematical operation.

Performing data transformation maps data from an original format into the format expected by an appropriate application or a format more convenient for a particular assumption or purpose. This includes value conversions or translation functions, as well as normalizing of numeric values to conform to the minimum and maximum values.

As we've used R earlier in this chapter, we can see that the syntax of a very simple example of this process is simple. For example, a data scientist may decide to transform a given value to the square root of the value:

data.dat$trans_Y <-sqrt(data.dat$Y) 

The preceding code example informs R to create a new variable (or column in the data.dat dataset) named trans_Y that is equal...