The study analyzing the relationship between TV viewing habits and children's test scores is classified as observational because it involves observing and measuring the behaviors and outcomes without manipulating any variables. In this context, researchers are likely examining existing data regarding children's TV viewing habits and their corresponding test scores, noting any correlations or patterns that emerge from this data.
In an observational study, the researcher does not intervene or control any aspects of the participants' behavior, instead allowing them to continue their usual activities. This type of study is beneficial for exploring real-world scenarios where ethical or practical constraints would make experimental manipulation difficult.
In contrast, an experimental study would require the researcher to actively manipulate variables, such as assigning children to different TV viewing plans and measuring outcomes, which is not the case here. A survey-based approach involves collecting data through questionnaires or interviews, which might be part of the study but does not necessarily capture the essence of how the viewing habits directly relate to test scores without experimentation. A controlled study typically relies on strict conditions and protocols, which is not applicable in this observational context where natural behaviors are being assessed.