Collocations for mistaken - adj.

be, prove, seem
That view seems mistaken.

badly, fundamentally, gravely, profoundly, sadly, seriously, sorely, very (much)
You are very much mistaken if you think that people will agree to these changes.

completely, entirely, quite, utterly
somehow

about
I think you're mistaken about the time.

Mistaken is used with these nouns:
assumption, belief, idea, identification, identity, impression, perception