1 The weight of a fire fighter would be an example of a continuous variable; since a fire fighter's weight could take on any value between 150 and 250 pounds.  Suppose we flip a coin and count the number of heads. The number of heads could be any integer value between 0 and plus infinity.
A postal code is a series of letters and/or digits appended to a postal address for the purpose of sorting mail. Once postal codes were introduced, other applications became possible. In February 2005, 117 of the 190 member countries of the Universal Postal Union had postal code systems.
ZIP Codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP, an acronym for Zone Improvement Plan, was chosen to suggest that the mail travels more efficiently, and therefore more quickly (zipping along), when senders use the code in the postal address. The basic format consists of five numerical digits. An extended ZIP+4 code, introduced in 1983, includes the five digits of the ZIP Code, a hyphen, and four additional digits that determine a more specific location within a given ZIP Code.