topic Selecting multiple random samples in SAS Programming

Selecting multiple random samples

DangIT — Tue, 03 Dec 2013 12:18:14 GMT

Hi,

I have a dataset that has a unique ID and 10 sources in which they come from, it looks like:

ID Source

1 A

2 B

3 C

4 D

5 D

6 C

etc.

What i'd like to do is create a new table selecting at Random a fixed number of observations from each source, for example my criteria may look like:

Source Random_Selection_count

A 500

B 300

C 250

D 100

etc.

I figure I can run the proc sql selection for each of the 10 sources then appending them together, but I am wondering if there is a simplier way?

Thanks in advance for your help.

Re: Selecting multiple random samples

data_null__ — Tue, 03 Dec 2013 12:33:23 GMT

SURVEYSELECT.

data source;
   input ID Source :$1.; 
   cards; 
1 A
2 B
3 C
4 D
5 D
6 C 
;;;;
   run; 
proc sort; 
   by source;
   run; 
proc print; 
   run; 
data size;
   input source :$1. _nsize_;
   cards; 
A 1
B 2
C 1
D 2
;;;;
   run; 
proc print; 
   run; 
proc surveyselect n=size data=source out=sample outall selectall; 
   strata source;
   run; 
proc print; 
   run;

Re: Selecting multiple random samples

DangIT — Tue, 03 Dec 2013 14:00:37 GMT

amazing, thank you very much.

Re: Selecting multiple random samples

data_null__ — Tue, 03 Dec 2013 15:57:06 GMT

You may not want OUTALL. SELECTALL selects the entire strata when _NSIZE_ is bigger than the number of obs. use REPS options if you want more than one sample and you probably want to specify the SEED.

Re: Selecting multiple random samples

DangIT — Fri, 24 Jan 2014 15:42:09 GMT

Hi,

I'm revisiting this test, with a additional layer of complexity that i'm unsure about how to proceed.

I have a testing grid that look's like:

Group	Z	A	B	C	D	E	F	G	H	I	J	Total per Group
Group 1	24,100	991	991	991	1,011							28,084
Group 2	24,099	991	991	991	1,010	1,295	1,322	1,322	1,321	1,321	1,322	35,985
Group 3	24,100	991	991	991	1,011	1,295	1,321	1,321	1,322	1,321	1,321	35,985
Group 4	24,100	991	991	991	1,011	1,295	1,322	1,321	1,321	1,322	1,321	35,986
Total	96,399	3,964	3,964	3,964	4,043	3,885	3,965	3,964	3,964	3,964	3,964	136,040

Where I have 4 Groups comprised of a sample from the following Sources (A-Z).

I'm not sure how I can assign a random sample for each group across the different Sources.

Your help greatly appreciated, thank you.