Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: RE: percentiles


From   "Steichen, Thomas" <STEICHT@RJRT.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: percentiles
Date   Fri, 11 Oct 2002 12:06:52 -0400

Don Spady writes:
> I am trying to use the command "pctile" to get percentiles 
> of the values in a variable.  The values are individual ages.
> I have used the commands:
> pctile  pct=age
> pctile pct=age, genp(pctAge)
> but when I run it and then list the first 10 instances I get
> 
> . list pct age in 1/10
> 
>            pct       age
>   1.         9        14
>   2.         .        17
>   3.         .         1
>   4.         .        14
>   5.         .         5
>   6.         .        12
>   7.         .        14
>   8.         .         7
>   9.         .         9
>  10.         .         0
> 
> The ages run from 0 to 17 and are fairly evenly distributed.
> ?? Why don't I get any values in the pct column and what does 
> the '9' mean.

9 is the median.

-pctile- splits the data into k=2 groups unless you specify the 
-nquantiles()- option and reports the cutpoints for k-1 groups
in the new variable (pct - in your case). With two groups, the 
cutpoint is the median.  -genp()- specifies the variable that 
contains the percentages in the two groups.

Tom
CONFIDENTIALITY NOTE:  This e-mail message, including any attachment(s), contains information that may be confidential, protected by the attorney-client or other legal privileges, and/or proprietary non-public information.  If you are not an intended recipient of this message or an authorized assistant to an intended recipient, please notify the sender by replying to this message and then delete it from your system.  Use, dissemination, distribution, or reproduction of this message and/or any of its attachments (if any) by unintended recipients is not authorized and may be unlawful.




© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index