Change the screen size and dpi

Is there a way to make Android think it has a different screen size and dpi than what was programmed in its factory settings?

I'm asking because we bought a 7-inch tablet recently, and its interface is too large for a 7-inch tablet. I installed System Info Droid and it confirmed what I suspected: The tablet thinks its screen is 4.86 inches with 192dpi.

Is there a way to fix this and tell it its screen is 7 inches and 133dpi?

The tablet is Genx GX7-3GS running Android 4.2.2.