The United States currently has approximately 287 Numbering Plan Areas (NPAs) in service, corresponding to geographic regions.

The United States currently has approximately 287 Numbering Plan Areas (NPAs) in service,

corresponding to geographic regions. Each NPA is identified by a three-digit code, commonly called an

area code. Suppose that you want to choose an SRS of 15 of these area codes for a study of available

telephone numbers. Label the codes 001 to 287 and use the Excel function RANDBETWEEN to a random

sample. Hint, for information on the RANDBETWEEN function see the website, http://www.excel-

easy.com/examples/random-numbers.html.