A toothache is a pain in or around a tooth that may be caused by: 1  Tooth decay. 2  Abscessed tooth. 3  Tooth fracture. 4  A damaged filling. 5  Repetitive motions, such as chewing gum or grinding teeth.
A correlational study determines whether or not two variables are correlated. This means to study whether an increase or decrease in one variable corresponds to an increase or decrease in the other variable.
There are many types of correlational research. The commonality among all types of correlational research is that they explore relationships between variables. Where descriptive research only described what was going on, correlational research talks about the link between different things.