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.
Technically, they are a type of correlational study. Quasi-experiments usually select only a certain range of values of an independent variable, while a typical correlational study measures all available values of an independent variable.