In order to assess the effects of exercise on reducing cholesterol, a researcher took a random sample of fifty people from a local gym who exercise regularly and another random sample of fifty people from the surrounding community who did not exercise regularly. They all reported to a clinic to have their cholesterol measured. The subjects were unaware of the purpose of the study, and the technician measuring the cholesterol was not aware of whether or not subjects exercised regularly. This is a(n) .a. observational study
b. experiment, but not a double blind experiment
c. double blind experiment
d. matched pairs experiment
e. block design