Correlational studies measure two variables and examine how they relate to each other without manipulating either one of them.
This occurs when both variables increase or decrease together, like height and weight in humans - as height increases, typically so does weight.
This happens when one variable increases while the other decreases, like time spent watching TV and grades - as TV time goes up, grades often go down.
A statistical measure that calculates the strength and direction of a correlation. It's like a scorecard telling how closely two things are related.