Adevelopmental psychologist believes that increased tv watching by young children is responsible for a decline in reading scores when these children enter school. to explore her hypothesis, she records the tv watching habits of toddlers in a suburban community. she examines these habits again when the children enter kindergarten and once more when they complete first grade. this method is

Longitudinal study  

Explanation:

Longitudinal study is known to be a type of research study in which research is conducted about a sample of individuals at regular interval in order to determine the effect pertaining to development and changes which occur or happen overtime. This form of research permits researchers to study the same sample of people repeatedly throughout the time of the research and make comparison. Thus, it cost a lot of money and time.