Premise: "A white dog is trying to catch a ball in midair over a grassy field."
Hypothesis: "The dog is chasing a ball that someone threw."
Do we know that the hypothesis entailed by the premise? Stream of thoughts:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A dog trying to catch a ball doesn't necessarily imply someone threw the ball.
Therefore, the answer is it is not possible to tell.