premise: A large group of people riding brown and white horses. hypothesis: A large group of kids riding little horses.
neutral: The word 'people' can be used to describe human beings of any age at all, it can also be used to describe multiple ages within a group - therefore it cannot be assumed that the people in question are kids, or any other age range.  Also, while children might commonly ride little horses, they don't always do so; the size of a horse cannot be determined from the color of the horse, nor from the age of the people riding it.