#### Overview of this book

Businesses today operate online and generate data almost continuously. While not all data in its raw form may seem useful, if processed and analyzed correctly, it can provide you with valuable hidden insights. The Data Analysis Workshop will help you learn how to discover these hidden patterns in your data, to analyze them, and leverage the results to help transform your business. The book begins by taking you through the use case of a bike rental shop. You'll be shown how to correlate data, plot histograms, and analyze temporal features. As you progress, you’ll learn how to plot data for a hydraulic system using the Seaborn and Matplotlib libraries, and explore a variety of use cases that show you how to join and merge databases, prepare data for analysis, and handle imbalanced data. By the end of the book, you'll have learned different data analysis techniques, including hypothesis testing, correlation, and null-value imputation, and will have become a confident data analyst.
Preface
1. Bike Sharing Analysis
Free Chapter
2. Absenteeism at Work
3. Analyzing Bank Marketing Campaign Data
4. Tackling Company Bankruptcy
5. Analyzing the Online Shopper's Purchasing Intention
6. Analysis of Credit Card Defaulters
7. Analyzing the Heart Disease Dataset
8. Analyzing Online Retail II Dataset
9. Analysis of the Energy Consumed by Appliances
10. Analyzing Air Quality

# Correlation

In this section, we will cover correlation – what does correlation mean, and how do we check the correlation between the `DEFAULT` column and other columns in our dataset?

Correlation measures the degree of dependency between any two variables. Say, for example, we have two variables, A and B. If the value of B increases when the value of A is increased, we say the variables are positively correlated. On the other hand, if the value of B decreases when we increase the value of A, we say the variables are negatively correlated. There could also be a situation where an increase in the value of A doesn't affect the value of B, for which we say the variables are uncorrelated.

The value of a correlation coefficient can vary between -1 to 1, with 1 being a strong positive correlation and -1 a strong negative correlation.

By studying the correlation between the `DEFAULT` column and other columns with the help of a heatmap, we can figure out which column/variable...