Welcome to Android Central! That's usually related to poor cell signal. If your signal is poor, the phone needs to expend more battery trying to latch on to the signal. That screenshot shows only two bars, so if it's usually like that or worse, that might be the reason.
That's been the fix so far. Until Samsung gets the coding fixed the way to get cell standby down and get much better battery life is to only have WiFi on when you need it. It will be fixed with a software update but, right now that's the best fix.Telling someone to turn off WiFi isn't advice. Not everyone has unlimited data. It's simply unacceptable that so many are having this issue with an $800 phone in 2015
It's simply unacceptable that so many are having this issue with an $800 phone in 2015