1: no real translation - the word after the number defines the number of viewers. You could say "listenership". The term also means "engaged".
You would also use the term, when explaining a 4 x 4 - that in addition to the rear axle, the front axle was also 'engaged' (zugeschalted). Example: ".......daß die Zuschaltung des Vorderradantriebes nur im Geländegang ..."
To find out what people are watching, meters installed in the selected sample of homes track when TV sets are on and what channels they are tuned to. A "black box," which is just a computer and modem, gathers and sends all this information to the company's central computer every night. Then by monitoring what is on TV at any given time, the company is able to keep track of how many people watch which program.
Small boxes, placed near the TV sets of those in the national sample, measure who is watching by giving each member of the household a button to turn on and off to show when he or she begins and ends viewing. This information is also collected each night.
The national TV ratings largely rely on these meters. To ensure reasonably accurate results, the company uses audits and quality checks and regularly compares the ratings it gets from different samples and measurement methods.
2: "was vermutest Du" can best be translated with "what do you think". Contrary to some opinions, you not only need to be a "native speaker" but must also master the other language, English in this case. Most folks are not really fluent in both, or at least they cannot 'think' in both - they simply speak German, with a basic understanding of some English. hence some answers are not quite on the mark, when it comes to more difficult points of translations.
fluent in both languages