#### Overview of this book

Predictive Analytics Using Rattle and Qlik Sense
Credits
www.PacktPub.com
Preface
Free Chapter
Creating Your First Qlik Sense Application
Clustering and Other Unsupervised Learning Methods
Decision Trees and Other Supervised Learning Methods
Model Evaluation
Visualizations, Data Applications, Dashboards, and Data Storytelling
Developing a Complete Application
Index

## Correlations among input variables

An important step is to identify relationships among input variables. To measure this relationship, we use the correlation coefficient. Correlation coefficient is a number between +1 and -1. When two variables have a correlation coefficient close to +1, they have a strong positive correlation. A coefficient of exactly +1 indicates a perfect positive fit. A positive correlation between two variables means that both variables increase and decrease their values simultaneously. A correlation coefficient between two variables close to -1 shows that both variables have strong negative correlation. When two variables have a negative correlation, the value of one of the variables increases when the value of the other variable decreases. A correlation coefficient close to 0 or a weak correlation between two variables means that there is no linear relationship between those variables.

Coming back to the Titanic passenger list, I've selected the Explore tab, the Correlation...