" People were asked questions to learn how much of what they had been told by their preferred news source was misinformation."

It is absolutely impossible for people to know what percent of their news is bogus. Knowing that would require a reference source that was certified 100% accurate by people who are both omniscient and 100% honest. {insert laughter here}

Fox owner Rupert Murdoch has been publicly endorsing Hillary for at least the last two years. Fox employees have routinely stated that stories (true or not) that might embarrass Ms. Clinton are spiked.