Cluster sampling refers to a type of sampling method . With cluster sampling, the researcher divides the population into separate groups, called clusters. Then, a simple random sample of clusters is selected from the population. The researcher conducts his analysis on data from the sampled clusters.
If you are running around an actual football field (100 yds x 50 yds) a mile would be 5.9 laps (1 mi = 1760 yds/300 = 5.86667). A standard racetrack around a football field should be 440 yds, so 4 laps should be a mile there (1760/440 = 4).
THE FIELD. The field measures 100 yards long and 53 yards wide. Little white markings on the field called yard markers help the players, officials, and the fans keep track of the ball. Probably the most important part of the field is the end zone. It's an additional 10 yards on each end of the field.