topic Re: getting a standard deviation from proc sql in Statistical Procedures

getting a standard deviation from proc sql

lmyers2 — Sat, 10 Feb 2018 23:57:53 GMT

Hello,

I created a new variable called "Indem" that is a mean (sum/N) in proc SQL and it works. However, I'd like to get a standard deviation from this mean. I think there is a function within proc sql that is STD but I don't see sample code for it on the SAS website. Does anyone know where it goes and how to format?

Many thanks!!!

Laura

proc sql;
create table cpc as select Paid, 
Sum(Indemnity)/count(CASE_ID) as Indem,
from datahave group by Paid;
quit;

Re: getting a standard deviation from proc sql

art297 — Sun, 11 Feb 2018 00:35:45 GMT

SAS has functions to calculate both mean and standard deviation in sql. e.g.:

             avg(age) as Mean format 10.2, 
             std(age) as std  format 10.2 label 'Std Dev'

The following paper shows most of the others: www2.sas.com/proceedings/forum2007/072-2007.pdf

Art, CEO, AnalystFinder.com

Re: getting a standard deviation from proc sql

PaigeMiller — Sun, 11 Feb 2018 12:52:34 GMT

@lmyers2 wrote:

Hello,

I created a new variable called "Indem" that is a mean (sum/N) in proc SQL and it works. However, I'd like to get a standard deviation from this mean.

Do you mean to say "standard deviation of the mean"??

If that's what you mean, you can program this as a simple formula, std(indemnity)/sqrt(n), or you can use PROC MEANS/PROC SUMMARY to compute the MEAN and the standard deviation of the mean (STDERR) without you having to write the formula yourself.

In fact, PROC MEANS/PROC SUMMARY is a superior method for another reason. Doing the math as you have

Sum(Indemnity)/count(CASE_ID) as Indem,

will produce the WRONG mean if there are missing values in Indemnity but not in CASE_ID, or vice versa. Your standard deviation calculation will also be wrong in this case.

Re: getting a standard deviation from proc sql

Reeza — Sun, 11 Feb 2018 03:27:47 GMT

@lmyers2 wrote:

I think there is a function within proc sql that is STD but I don't see sample code for it on the SAS website. Does anyone know where it goes and how to format?

List of functions is here, with some examples below the list:

http://support.sas.com/kb/25/279.html