BookmarkSubscribeRSS Feed
🔒 This topic is solved and locked. Need further help from the community? Please sign in and ask a new question.
mona4u
Lapis Lazuli | Level 10

Hi All, 

I want to calculate the association within subjects. Each subject has left and right eye and they have a grade for the test is aval and the count for the times they have the grade each time they did the test is aval_count. 

I tried to test the association by the following code and SAS didn't provide me the desired output. 

I'm open to suggestions. 

 

 

data have;
input usubjid :$20. aval alat $ aval_count;
datalines;
7751.000061 1.5 Left 3
7751.000061 1 Right 1
7751.000061 1.5 Right 2
7751.000824 1.5 Left 2
7751.000824 2 Left 1
7751.000824 1.5 Right 1
7751.000824 2 Right 2
7751.002940 1 Left 2
7751.002940 1.5 Left 1
7751.002940 1 Right 2
7751.002940 1.5 Right 1
7751.003306 1.5 Left 2
7751.003306 2 Left 1
7751.003306 1.5 Right 3
7751.003520 1.5 Left 3
7751.003520 1 Right 1
7751.003520 1.5 Right 2
7820.27252833 0 Left 3
7820.27252833 0 Right 3
7820.27253759 0 Left 3
7820.27253759 0 Right 3
7820.27253776 0 Left 3
7820.27253776 0 Right 3
7820.27265336 0 Left 3
7820.27265336 0 Right 3
7820.27270639 0 Left 3
7820.27270639 0 Right 2
7820.27270639 1 Right 1
7820.29087999 0 Left 3
7820.29087999 0 Right 3
7820.40672349 0 Left 3
7820.40672349 0 Right 3
7820.45921053 0 Left 3
7820.45921053 0 Right 3
7820.50956338 0 Left 3
7820.50956338 0 Right 3
7820.51799541 0 Left 1
7820.51799541 0 Right 1
7820.51968934 0 Left 2
7820.51968934 1 Left 1
7820.51968934 0 Right 2
7820.51968934 1 Right 1

run;

proc freq data=have;
tables USUBJID*ALAT*aval/ chisq measures;
weight aval_count;
run;

 

 

Thanks, 

Mona 

1 ACCEPTED SOLUTION

Accepted Solutions
Reeza
Super User
What does correlated mean though? If there isn't a clear definition of what you're trying to do it's almost impossible to write the code.
You have paired data but a few measures, one for each eye I assume. I'd start by graphing it and seeing what that shows I suspect. Weight the scatter plot by the # of tests as a starting point.

View solution in original post

8 REPLIES 8
ballardw
Super User

Your counts within levels of Usubjid as shown are pretty small for just about any purpose with 6 seeming to be the typical number of "grades". Splitting that by just about any other variable makes the cell counts so small to be almost meaningless.

 

I do find the structure of your Usubjid to be a tad odd. Typically most identification schemes don't go in for decimals. By any chance did you actually intend to this test using just the first 4 characters of the Usubjid value?

 

Please describe the "desired output" since it appears that you have some idea of what you wanted. Please not that Chi-squares don't like cells with 0 counts as you likely got in your output.

 

You might try using Usubjid as a BY variable and remove it from the Tables statement. That would at least reduce the number of 0 cell sizes but then you are going to have groups with only one value of Aval. Which isn't really going to be very testable.

mona4u
Lapis Lazuli | Level 10

aval 0, 1, 1.5 2 is a categorical variable. 

aval count counts the number of each aval grades happen in each eye. 

 

I want the test of association within eyes for each subject between all subjects. 

Proc freq doesn't provide me any statistics when I use the proc freq the way I use it. Maybe there is a better way to get my desired outcomes. 

 

 

Reeza
Super User
What does this mean: "I want the test of association within eyes for each subject between all subjects."? What is that as a hypothesis?
mona4u
Lapis Lazuli | Level 10

test the association between eyes for each subject and for all subjects

Reeza
Super User
That's not a hypothesis 😞
mona4u
Lapis Lazuli | Level 10

I don't have a hypothesis I just want to know how they are correlated either using this procedure or other procedures. 

 

 

Thanks 

Reeza
Super User
What does correlated mean though? If there isn't a clear definition of what you're trying to do it's almost impossible to write the code.
You have paired data but a few measures, one for each eye I assume. I'd start by graphing it and seeing what that shows I suspect. Weight the scatter plot by the # of tests as a starting point.
mona4u
Lapis Lazuli | Level 10

Hi Reeza, 

I want to see the correlation between the subjects' scores between their eyes left and right. 

this is a repeated measurement and aval record the grade of the test. 

Not sure how to start as the data is a bit complicated. 

 

 

Thanks, 

Mona 

Ready to join fellow brilliant minds for the SAS Hackathon?

Build your skills. Make connections. Enjoy creative freedom. Maybe change the world. Registration is now open through August 30th. Visit the SAS Hackathon homepage.

Register today!
Mastering the WHERE Clause in PROC SQL

SAS' Charu Shankar shares her PROC SQL expertise by showing you how to master the WHERE clause using real winter weather data.

Find more tutorials on the SAS Users YouTube channel.

Discussion stats
  • 8 replies
  • 914 views
  • 1 like
  • 3 in conversation