Drinking more than 4 cups of juice a day may cause cavities in young children. This was a conclusion reached in a study of 570 healthy children aged 2 - 6 years old, in which doctors asked parents to keep a daily record of the amount of juice their children drank over a nine month period. The doctors found that those who drank more than 4 cups daily tended to have more cavities than children who drank less than 4 cups per day. This is an example of This is an example of an experiment with one independent variable: the number of cups of juice a correlational study a dependent variable measured on a physiological scale a matched groups design a within-subjects design