Book Image

Time Series Analysis with Python Cookbook

By : Tarek A. Atwan
Book Image

Time Series Analysis with Python Cookbook

By: Tarek A. Atwan

Overview of this book

Time series data is everywhere, available at a high frequency and volume. It is complex and can contain noise, irregularities, and multiple patterns, making it crucial to be well-versed with the techniques covered in this book for data preparation, analysis, and forecasting. This book covers practical techniques for working with time series data, starting with ingesting time series data from various sources and formats, whether in private cloud storage, relational databases, non-relational databases, or specialized time series databases such as InfluxDB. Next, you’ll learn strategies for handling missing data, dealing with time zones and custom business days, and detecting anomalies using intuitive statistical methods, followed by more advanced unsupervised ML models. The book will also explore forecasting using classical statistical models such as Holt-Winters, SARIMA, and VAR. The recipes will present practical techniques for handling non-stationary data, using power transforms, ACF and PACF plots, and decomposing time series data with multiple seasonal patterns. Later, you’ll work with ML and DL models using TensorFlow and PyTorch. Finally, you’ll learn how to evaluate, compare, optimize models, and more using the recipes covered in the book.
Table of Contents (18 chapters)

Chapter 8: Outlier Detection Using Statistical Methods

In addition to missing data, as discussed in Chapter 7, Handling Missing Data, a common data issue you may face is the presence of outliers. Outliers can be point outliers, collective outliers, or contextual outliers. For example, a point outlier occurs when a data point deviates from the rest of the population—sometimes referred to as a global outlier. Collective outliers, which are groups of observations, differ from the population and don't follow the expected pattern. Lastly, contextual outliers occur when an observation is considered an outlier based on a particular condition or context, such as deviation from neighboring data points. Note that with contextual outliers, the same observation may not be considered an outlier if the context changes.

In this chapter, you will be introduced to a handful of practical statistical techniques that cover parametric and non-parametric methods. In Chapter 14, Outlier Detection...