Question

classify the following study.
people should brush their teeth at least twice a day for at least two to three minutes with each brushing.
for a statistics class project, you ask a random number of students at your school questions concerning their tooth brushing activities.
observational study
experiment
survey

Explanation:

An observational study simply observes and records data without interfering. An experiment manipulates variables. A survey collects data by asking questions. Here, asking students questions (survey method) about their tooth - brushing (no manipulation, just data collection via questions).

Answer:

Survey