Z-test
Hypothesis test about a single mean if the sample is large enough and drawn
from a normal population. A small sample uses a T-test.


ZIP +4
Designation by the U.S. Postal Service for the nine-digit coding structure.


ZIP code
Registered trademark of the U.S. Postal Service; a five-digit or nine-digit code
identifying regions in the United States.


ZIP code demographics
The demographic characteristics of a population living in a particular ZIP code.