The rear disk on the N300 is about 75% the size of the front brake.
When braking, the momentum of the bike tends to shift more weight onto the front wheel. This means the front tire will have more grip, and the rear tire less grip (since friction force is proportional to normal force). In general, this difference is larger on a "sport" bike than a cruiser due to geometry. Rear brakes are intentionally designed to be weaker than front brakes for this reason.
That doesn't mean that yours is definitely working fine, just that noticing a weaker rear brake doesn't always mean something is wrong either.
To put it in another perspective, let's assume the weight is pretty evenly distributed between front and rear wheels when stationary (CofG halfway between wheels).
Now consider the "stoppie" where you brake so aggressively, the back tire comes off the ground. It's pretty clear that no amount of rear brake pressure is going to have any effect on stopping.
Any brake application between these two cases is going to shift the weight (and therefore available friction force with the ground) to the front tire. The harder you brake, the less effective the rear brake becomes, and the more effective the front brake becomes. Also, this reduction in friction force means the rear wheel is more likely to lock up, since it has less grip on the ground.
Typical values for braking bias under "normal" conditions suggest between 70%-80% of your braking is from the front wheel.