Classify each description as either an observational study or an experiment.

In a study on the effects of core exercise on back pain, some participants are asked to perform core exercises daily while the other participants perform alternative exercises daily. Back pain is assessed after one month.

Child psychologists seek to determine the link between peer pressure and bullying. They conduct a survey of 5000 adolescents asking them how often they have been bullied or have bullied others.

Agricultural scientists seek to test the effects of a new pesticide on corn crops. Half of the participating farmers are assigned the new pesticide and the other half continue using an alternative pesticide. The crops are compared after two seasons.

Students from 10 schools are divided into groups by researchers, those that participate in musical activities and those that do not. Student grades are monitored for a year to determine if those who participate in musical activities achieve higher grades.

A cancer study began by surveying male patients between the ages of 35 and 55 at a local hospital about their exercise routine. The health of these men is tracked over 10 years to determine the effect of exercise on lowering the risk of cancer.

Researchers studying how exercise affects cholesterol sample 50 people who exercise regularly and 50 who do not. Blood was drawn from each person and serum cholesterol was measured.