How do certain TV shows know their ratings??

Question

I know, your expression would be: "oh why would you ask that?!" I dont know ,I am just curious

Answer 1

The Nielsen Media Research Company tracks a sample group of American TV viewers either through a small computer attached to the viewer's TV or through a written diary that the viewers keep. Through these two methods, they do a statistical calculation that estimates how many households are watching particular shows.

Answer 2

the nielsen media research produces the tv ratings. networks, ad agencies, producers, etc., get the info or ratings from this company, nielsen also publishes a partial list every wednesday on the newspaper-usa today. nielsen measures viewing habits (the basis of the ratings) thru statistical sampling either thru the diary or the metering equipment connected to a participant household's tv.