Set period of time-series data                  [STB-7: sts2; STB-16: sts4.1]
------------------------------

	^period^ [ # | word | # word ]

where word is {^a^nnual | ^s^emiannual | ^q^uarterly | ^m^onthly | ^w^eekly | ^d^aily }
corresponding
to the numbers    ^1         2            3         12        52      365^


Remarks
-------

^period^ sets the period (frequency) of the time-series data.  The period is 
used by commands such as ^growth^.  ^period^ without argument displays the per-
iod currently in use.  If the period is not set, each observation is assumed
to represent annual data, known as ^period 1 annual^.

The period # records the number of observations per year in the data.  Thus,
^period 1^ means annual data and ^period 12^ means monthly data.  

By specifying "^period^ # word", you can create your own correspondence of 
number of observations "per year" and words.  For instance, "^period 1 hourly^"
or "^period 24 daily^".  The idea is that a 1-unit change in # should be a
meaningful period for normalization of, for instance, growth rates.

	
Examples
--------

 . ^period 1^
 . ^period annual^

 . ^period m^

 . ^period 24 daily^
 

Author
------
 
Sean Becketti, Stata Technical Bulletin


Also see
--------

    STB:  sts2 (STB-7), sts4 (STB-15)
On-line:  ^help^ for ^datevars^, ^findsmpl^, and ^growth^