Google Puzzlement?

For some wierd reason all of a sudden Google is showing one of my
internal pages instead of my index home page at my serp? Why would that
happen? The index page homepage has higher pr and a lot more backlinks
then the internal page. Not only that but my search terms for my serps
are two words and the internal page is the two words put together as one
word (mispelling type page) for people who rush and do the typo error.
Other then that both pages are equally optimized as far as on page
coding goes so I can't figure out why they are doing this all of a
sudden and showing the internal page instead of the homepage? Anybody
have any ideas?