I'm not sure if this is a run-on sentence.

Stock prices rose slightly yesterday. The TSE average up 16.9 points and the Canadian Exchange index up 3.2.

2 answers

There is no run-on here, but there's definitely a fragment. The first sentence is fine. The second is not a complete sentence.
It's just missing a verb. If that were there, then it would need a comma, since it would be a compound sentence.

Just FYI, use "whether" when a choice is to be made; "if" introduces a conditional clause.

As it stands, you'd likely be sure, if it weren't a run-on sentence. If it's run-on, then you're not sure.