topic Re: How to get a 10% of the population for each state in SAS Programming

How to get a 10% of the population for each state

Cherry — Thu, 16 Feb 2012 13:51:55 GMT

I have a business scenario where I have to select only 10% of the total observations for each state. for ex:

The final output should have 10 % of the population from each state. Please assist me with the code. I tried using Proc SurveySelect but did not work.

Re: How to get a 10% of the population for each state

Haikuo — Thu, 16 Feb 2012 14:05:20 GMT

You would have to share more details about your problems, such as your code and the log involved. As it seems to me, proc surveyselect works as being expected. Please see the following example:

proc sort data=sashelp.class out=have;

by sex;

run;

Proc SurveySelect data=have out=want samprate=0.1;

strata sex;

run;

proc print;run;

Not sure any special method or algorithm you are applying will make a difference, so more details will be needed.

Regards,

Haikuo

Re: How to get a 10% of the population for each state

Cherry — Thu, 16 Feb 2012 15:17:06 GMT

Hi,

I have a business scenario where I have to select only 10% of the total observations for each state. for ex:

State	total observations	No of obs to be output (10% of total)
Northeast	43543	4355
Northwest	12323	1233
Southeast	876578	87658
Southwest	387482	38749

The final output should have 10 % of the population from each state. Please assist me with the code. I tried using Proc SurveySelect but did not work.

Re: How to get a 10% of the population for each state

Tom — Thu, 16 Feb 2012 15:22:09 GMT

If you only want approximately 10% then just use a random number generator to give each obs 10% chance of being selected.

data want ;

set have ;

if ranuni(0) <= .10 then output;

run;

Proc SurveySelect should work for this problem. Could you post the code you tried?

Re: How to get a 10% of the population for each state

art297 — Thu, 16 Feb 2012 15:26:43 GMT

Did you try the code proposed by Hai.Kuo? Seems like it should work:

proc sort data=yourdatafilelibandname out=have;

by state;

run;

Proc SurveySelect data=have out=want samprate=0.1;

strata state;

run;

How to get a 10% of the population for each state

FriedEgg — Thu, 16 Feb 2012 17:33:49 GMT

The following will not take a random sample but it will return every nth record from each by group.

proc sql;

create view class as

select *

from sashelp.cars

order by origin;

quit;

data want;

set class;

by origin;

array accum&sysindex[1] _temporary_; *temp so no need to drop later;

if first.origin then accum&sysindex[1]=10;

accum&sysindex[1]+1;

if accum&sysindex[1]>10 then

do;

accum&sysindex[1]=accum&sysindex[1]-10;

output;

end;

run;

proc sql;

select a.origin,total,output

from (select origin,count(1) as total from sashelp.cars group by origin) a

left join (select origin,count(1) as output from want group by origin) b on a.origin=b.origin;

quit;

Origin	total	output
Asia	158	16
Europe	123	13
USA	147	15

How to get a 10% of the population for each state

ballardw — Fri, 17 Feb 2012 15:13:55 GMT

Cherry wrote:

Hi,

I have a business scenario where I have to select only 10% of the total observations for each state. for ex:

State	total observations	No of obs to be output (10% of total)
Northeast	43543	4355
Northwest	12323	1233
Southeast	876578	87658
Southwest	387482	38749

The final output should have 10 % of the population from each state. Please assist me with the code. I tried using Proc SurveySelect but did not work.

HOW did it not work? No output at all? Expected number of observations not selected? What did your code look like?