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).
How many laps is 500 yards? The standard length for a running track is 400 meters; 500 yards converts to 457.2 meters, and so 500 yards would take up slightly more than 1 1/8 laps. Starting at the universal finish line on the track, this would require a lap plus 57.2 more meters.