Book Image

Statistics for Machine Learning

By : Pratap Dangeti
Book Image

Statistics for Machine Learning

By: Pratap Dangeti

Overview of this book

Complex statistics in machine learning worry a lot of developers. Knowing statistics helps you build strong machine learning models that are optimized for a given problem statement. This book will teach you all it takes to perform the complex statistical computations that are required for machine learning. You will gain information on the statistics behind supervised learning, unsupervised learning, reinforcement learning, and more. You will see real-world examples that discuss the statistical side of machine learning and familiarize yourself with it. You will come across programs for performing tasks such as modeling, parameter fitting, regression, classification, density collection, working with vectors, matrices, and more. By the end of the book, you will have mastered the statistics required for machine learning and will be able to apply your new skills to any sort of industry problem.
Table of Contents (16 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Forward propagation and backpropagation


Forward propagation and backpropagation are illustrated with the two hidden layer deep neural networks in the following example, in which both layers get three neurons each, in addition to input and output layers. The number of neurons in the input layer is based on the number of x (independent) variables, whereas the number of neurons in the output layer is decided by the number of classes the model needs to be predicted.

For ease, we have shown only one neuron in each layer; however, the reader can attempt to create other neurons within the same layer. Weights and biases are initiated from some random numbers, so that in both forward and backward passes, these can be updated in order to minimize the errors altogether.

During forward propagation, features are input to the network and fed through the following layers to produce the output activation. If we see in the hidden layer 1, the activation obtained is the combination of bias weight 1 and weighted...