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.
A correlation is simply defined as a relationship between two variables. The whole purpose of using correlations in research is to figure out which variables are connected.