Is this statement an observation or an inference?

Question

The cat must be ill.

is that an observation or an inference

please explain your answer...

Answer 1

the statement is an inference. you came up with that inference from your observation. the cat probably have shown symptoms of being ill, and these things would be the observation. and so, the statement "the cat must be ill" is an inference.

Answer 2

An inference based on observation?

An observation generally doesn't involve a judgment or conclusion. Example:  "The cat has refused to eat any food for the past two days."

That would result in the inference "The cat must be ill."  

Answer 3

Observation: the cat isn't eating anything, and is not running around.  She's not responding when I call her. (these are all things you can see)

Inference: the cat must be ill (you infer from your observations that the cat is ill)