Good guess! You are correct. Sisko said it when he was ordered to host Dominion peace talks on the station. "Statistical Probabilities."
Ah, I was thinking of Classic Trek, Journey to Babel. No idea if it was said then though... Here's the next one... _ _ _ _ _ _ _ / _ / _ _ _ _ _ _ _ / _ / _ _ _ _ _ / _ _ _ / _ _ _ _ _ _ _ _ / _ _ _ _ / _ _ _ / _ _ _ _ / _ / _ _ _ / _ _ / _ _ _ _ / _ _ _ _ / _ _ _ / _ _ _ _ _ _
_ _ _ t _ _ _ / _ / _ _ _ _ _ _ _ / _ / s _ _ _ _ / _ _ _ / _ _ _ _ _ _ _ _ / _ _ _ _ / s _ _ / _ _ _ _ / _ / s _ _ / t _ / _ _ _ _ / _ _ t _ / _ _ _ / _ _ _ _ _ s
C _ _ t _ _ _ / _ / _ _ _ _ _ _ _ / _ / s _ _ _ _ / _ _ _ / _ _ _ _ _ _ _ _ / _ _ _ _ / s _ _ / _ _ _ _ / _ / s _ _ / t _ / _ _ _ _ / _ _ t _ / _ _ _ / _ _ _ _ _ s
C _ _ t _ _ n / _ / _ _ _ _ _ _ _ / _ / s _ _ _ _ / _ _ _ / _ _ _ _ _ _ n _ / _ _ _ _ / s _ _ / _ _ _ n / _ / s _ _ / t _ / _ _ _ _ / _ _ t _ / _ _ _ / _ _ _ _ _ s
C _ _ t _ _ n / _ / _ _ _ _ _ _ _ / _ / s _ _ _ _ / _ _ r / _ _ _ r _ _ n _ / _ _ r _ / s _ r / _ _ _ n / _ / s _ _ / t _ / _ _ _ _ / _ _ t _ / _ _ r / _ _ _ _ r s
C _ _ t _ _ n / _ / b _ _ _ _ _ _ / _ / s _ _ _ _ / _ _ r / _ _ _ r y _ n _ / _ _ r _ / s _ r / _ _ _ n / _ / s _ y / t _ / _ _ _ _ / _ _ t _ / _ _ r / _ r _ _ r s BTW, just realised I missed the first R in the last word.
C _ _ t _ _ n / _ / b _ _ _ _ v _ / _ / s _ _ _ _ / _ _ r / _ v _ r y _ n _ / _ _ r _ / s _ r / _ _ _ n / _ / s _ y / t _ / _ _ _ _ / _ _ t _ / _ _ r / _ r _ _ r s