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).
Confidence votes 473. 4 laps around a regular track=1 mile. Since the standard for tracks built in the last 20+ years is 400M, then you must go 9.344 meters further than 4 laps. Over 90% of the outdoor tracks in existence are only 400M and will thus require the extra 9.344 meters to equal a true mile.