It has been known for a while now that Fox News viewers are more ignorant of what is really happening in this country. That has been shown by several respected polls and studies. That's because Fox News doesn't bring viewers all the news -- just the news they think makes Republicans look good.
But it is even worse than that. As the charts above show (from the Washington Post / University of Maryland Poll), the Republicans that watch Fox News are more prone to believe conspiracies than Republicans that don't watch Fox -- and the difference is statistically significant.
Fox doesn't just cherry pick the news it likes, it also gives air time to conspiracy theories from right-wing Republicans. This makes their viewers not only ignorant, but conspiracy theory believers. The truth is that Fox is not a news channel. It is a propaganda channel for the Republican Party.