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help for ^mkquant^                                               (STB-25:  sg38)
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Create quantiles and save as a new variable
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    ^mkquant^ varname [weight] [^if^ exp] [^in^ range]^,^ ^g^enq^(^newvar1^)^
						[ ^genp(^newvar2^)^  ^n^umber^(^#^)^ ]


^aweight^s and ^fweight^s are allowed; see help @weights@.


Description
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^mkquant^ computes the p-th quantiles of varname, where p = i/n for
i = 0, 1,..., n, with n = # an integer specified by ^number(^#^)^.
The 0-th quantile is the minimum of varname and the 1-th quantile
is the maximum.


Options
-------

^genq(^newvar1^)^ is not optional.  The quantiles are stored in the new
    variable newvar1.  

^genp(^newvar2^)^ is optional.  If specified, the corresponding empirical
    probabilities p = i/n will be stored in the new variable newvar2.

^number(^#^)^ specifies the number of quantiles n = #.  It must be an integer.
    The default is 100.


Examples
--------

 . ^mkquant price, g(quant)^

 . ^mkquant price, genq(quant) n(50)^

 . ^mkquant price, genq(quant) genp(p) number(200)^

 . ^mkquant price, g(quant) genp(p) n(200)^


Methods and Formulas
--------------------

Let the data sorted in ascending order be x(1), x(2),..., x(N), with
corresponding weights w(1), w(2),..., w(N) (all equal to 1 if not specified). 
Let W(i) = [w(1) + w(2) + ... + w(i)]/[w(1) + w(2) + ... + w(N)].

Let q[p] be the p-th quantile of x for 0 < p < 1. 

		|  x(i)                   if W(i - 1) < p < W(i)
	q[p] =  {
		|  [(x(i) + x(i + 1)]/2   if p = W(i)

We define q[0] = x(1) and q[1] = x(N).


Author
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	Bill Sribney
	Stata Corporation
	702 University Drive East
	College Station, TX 77840
	Phone: 409-696-4600
	       800-782-8272
	Fax:   409-696-4601
        email: stata@@stata.com


Also see
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    STB:  STB-25 sg38
 Manual:  [5s] centile, [5s] egen, [5s] summarize
On-line:  help for @centile@, @egen@, @summarize@