Pre- Test and Post- Test Data

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Contributor
Posts: 27

Pre- Test and Post- Test Data

I have 70 variables are pre-test and another 70 variables are post-test. I am going to do the two-sample Wilcoxon test., but how do I format these variable so I will have a new variable called "time" that tells SAS the timepoint: pre=1 and post=2 for each pair?

 

70 Pre-test variables:                                                                     

PRETC1
PRETC2
PRETC3
PRETC4
PRETC5
PRETC6
PRETC7
PREEBC1
PREEBC2
PREEBC3
PREEBC4
PREEBC5
PREEBC6
PREEBC7
PREEBC8
PREEBC9
PREEBC10
PREEBC11
PRETOP1
PRETOP2
PRETOP3
PRETOP4
PRETOP5
PRETOP6
PRETOP7
PRETOP8
PRETOP9
PRETOP10
PRETOP11
PRETOP12
PRETOP13
PRETOP14
PRETOP15
PRETOP16
PRETOP17
PRETOP18
PRETOP19
PRETOP20
PRETOP21
PREMENT
PREMENTRANK1
PREMENTRANK2
PREMENTRANK3
PREMENTRANK4
PREMENTRANK5
PREMENTRANK6
PREMENTRANK7
PREMENTRANK8
PREMENTRANK9
PREMENTRANK10
PREMENTRANK11
PREMENTRANK12
PREMENTRANK13
PREMENTRANK14
PREMENTRANK15
PREMENTRANK16
PREMENTRANK17
PREMENTRANK18
PREMENTRANK18SPECIFY
PREMENTRANK19

 

 

 

70  Post-test variables:

POSTTC1
POSTTC2
POSTTC3
POSTTC4
POSTTC5
POSTTC6
POSTTC7
POSTEBC1
POSTEBC2
POSTEBC3
POSTEBC4
POSTEBC5
POSTEBC6
POSTEBC7
POSTEBC8
POSTEBC9
POSTEBC10
POSTEBC11
POSTTOP1
POSTTOP2
POSTTOP3
POSTTOP4
POSTTOP5
POSTTOP6
POSTTOP7
POSTTOP8
POSTTOP9
POSTTOP10
POSTTOP11
POSTTOP12
POSTTOP13
POSTTOP14
POSTTOP15
POSTTOP16
POSTTOP17
POSTTOP18
POSTTOP19
POSTTOP20
POSTTOP21
POSTMENT
POSTMENTRANK1
POSTMENTRANK2
POSTMENTRANK3
POSTMENTRANK4
POSTMENTRANK5
POSTMENTRANK6
POSTMENTRANK7
POSTMENTRANK8
POSTMENTRANK9
POSTMENTRANK10
POSTMENTRANK11
POSTMENTRANK12
POSTMENTRANK13
POSTMENTRANK14
POSTMENTRANK15
POSTMENTRANK16
POSTMENTRANK17
POSTMENTRANK18
POSTMENTRANK18SPECIFY
POSTMENTRANK19

                                                                  

Super User
Posts: 13,338

Re: Pre- Test and Post- Test Data

You may find reformatting the data to

When C1 C2 C3 ... EBC1 EBC2 EBC3 ...Top1 Top2 Top3 ...

where the first variable indicates Pre Or Post, such as 1 for Pre and 2 for Post.

 

Then your test would look like:

proc npar1way data=have wilcoxon correct=no data=React;
   class When;
   var C1;
   exact wilcoxon;
run;
Contributor
Posts: 27

Re: Pre- Test and Post- Test Data

Yes, I understand that I need a variable indicating the timepoint (pre or post). But I don't know how to reformat the data. Should I use transpose or anything?

Super User
Posts: 13,338

Re: Pre- Test and Post- Test Data


Denali wrote:

Yes, I understand that I need a variable indicating the timepoint (pre or post). But I don't know how to reformat the data. Should I use transpose or anything?


This is one way to transpose the data:

data want;
   set have;
   When = 1;
   C1=PRETC1; 
   C2=PRETC2; 
   C3=PRETC3; 
   C4=PRETC4; 
   C5=PRETC5; 
   C6=PRETC6; 
   C7=PRETC7; 
   /*all the other PRE variables go here*/
   output; 
   When = 2;
   C1=POSTTC1; 
   C2=POSTTC2; 
   C3=POSTTC3; 
   C4=POSTTC4; 
   C5=POSTTC5; 
   C6=POSTTC6; 
   C7=POSTTC7; 
   /*all the other POST variables go here*/
   output;

   keep when C1 - C7  /*and the other new variables from the left of the = signs*/
run; 

Careful use of arrays would shorten the code but I'll leave that as an exercise for the interested reader. Doing something like this by hand is good incentive to learn arrays.

 

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