how do they figure out how many people have watched a certain show/event?
They have a couple of ways.
1. Nielson families.
Certain families are chosen by demographic and given a device that tracks their viewing habits (In the old days they had to keep a viewing journal. ) Each family respresents a certain percentage of the viewing public.
2. Telephone polling.
They call a statistically significant number of people and ask them about their veiwing habits.
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