premise: How to treat ear mites<br>Look for redness and irritation. The inside of the ear will be red and irritated; however, while a red irritated ear can be a sign of ear mites, that in and of itself isn't a definitive symptom. If you don't see any other ear-mite symptoms or have any doubt, see your vet.
hypothesis: The outside of the ear will be red and irritated with ear mites. 
reason: It talked about the irritation on the inside of the ear but it didn't say anything about the outside. So maybe the outside is irritated, and maybe it's not,.... the text doesn't say one way or another because it just discusses the inside.