Is the 737NG hydraulically controlled or electronically controlled?
Of course it's hydraulic. 

Electric actuators or power-by-wire is actually a far more exotic technology than fly-by-wire, and the latter is a hard prerequisite for the former.

Normal fly-by-wire is still based on hydraulic systems, with the electrical FBW system controlling the valves. And even in power-by-wire systems, the final actuator is typically a small enclosed hydraulic unit.

The newer 737 MAX has a couple FBW elements (spoilers), but is still a manual system, well short of FBW or PBW.