topic Re: Paired T test in SAS Programming

Paired T test

Xinhui — Sun, 01 Dec 2019 19:49:07 GMT

Hi There

I have a dummy variable "d" and another variable "csrp"

I want use the paired T test to examine, the "csrp" is significant different between "0" and "1" group of "d'.

How should I code it?

Thanks in advance.

Re: Paired T test

PaigeMiller — Sun, 01 Dec 2019 19:56:35 GMT

Example:

https://documentation.sas.com/?docsetId=statug&docsetVersion=14.3&docsetTarget=statug_ttest_examples03.htm&locale=en

Re: Paired T test

ed_sas_member — Sun, 01 Dec 2019 20:17:39 GMT

Hi @Xinhui

The following code would perform a t-test (mean comparison of two groups defined by the CLASS statement)

proc ttest data=have;
	var csrp;
	class d; 
run;

Are you sure you want to perform a paired t-test? In this case, you need to define the couple of observations between the two groups. Do you have an ID variable to identify pairs?

In this case, you should have two variables (csrp value for each group; a pair by row) and the syntax would be:

proc ttest data=have;
	paired csrp1*csrp2;
run;

Re: Paired T test

Reeza — Sun, 01 Dec 2019 20:48:56 GMT

You need to restructure your data so that SAS knows which pairs go together. That means you need your data in a format like this:

ID    Pre    Post
1      5        8
2      4        8
3      6        7
....

You can use PROC TRANSPOSE to restructure your data and then run PROC TTEST as indicated by others.

Here's a tutorial on transposing from a long data set to a wide data set with examples that should get you started.
Long to Wide:
https://stats.idre.ucla.edu/sas/modules/how-to-reshape-data-long-to-wide-using-proc-transpose/

@Xinhui wrote:

Hi There

I have a dummy variable "d" and another variable "csrp"

I want use the paired T test to examine, the "csrp" is significant different between "0" and "1" group of "d'.

How should I code it?

Thanks in advance.

Re: Paired T test

DrAbhijeetSafai — Mon, 16 Dec 2024 08:01:42 GMT

This was very useful @ed_sas_member , many thanks!

- Dr. Abhijeet Safai