Regression and Correlation are the most used and most abused tools in research.

Regression and Correlation are the most used and most abused tools in research. People are quick to jump to conclusions that if a relationship exists between two variables, then one must cause the other. There are many reasons why two variables can be related without causality. For example, there is a strong inverse relationship between the sale of ice cream and the number of reported cases of the flu -- does ice cream cure the flu? Of course not, but more ice cream is consumed in the summer, when the flu is minimized, thus there is a seasonal relationship, not a causal one. There is also a relationship between the seat belt lights turning on in an airplane and the existence of turbulence in flight, but the lights do not cause the turbulence.