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duckypooh
Calcite | Level 5

Hello! 

 

Sorry if my question seem basic but i am new to statistical analysis and would to ask which is the best test to determine association between variables and outcome if: 

 

1. I have a small sample size ~15 

2. 1 binary independent variable 

3. A mixture of continuous and categorical dependent variables 

 

TIA! 

7 REPLIES 7
PaigeMiller
Diamond | Level 26

With a sample size of ~15, no test will have a lot of power. 

 

For continuous dependent variables, I would use PROC GLM Analysis of Variance (assuming the errors are iid normal), and PROC NPAR1WAY otherwise.

 

For categorical variables, I would use a contingency table in PROC FREQ and do the Chi-Squared test.

--
Paige Miller
Ksharp
Super User
You didn't post your data yet ?
1) Fisher Exact Test ?
proc freq;
table a*b/chisq fisher;
exact fisher;
run;


2) Logistic Regression ?
proc logistic;
model y=

3) General Linear Model ?
proc glm
SteveDenham
Jade | Level 19

One more choice, based on the small sample size, would be to use the EXACT option in PROC LOGISTIC.  However (and this is critical), you need to look at the cross tabulation of your results versus the categorical variables.  With this small sample size, you are almost certain to have what is called complete or partial separation.  I would suggest removing from the analysis any variables that show complete separation - you know what the outcome will be once you have the value of the independent categorical variable.  If you still run into partial separation issues, then you might consider using PROC GENMOD and the alternating logistic regression method outlined here0

:https://documentation.sas.com/?docsetId=statug&docsetTarget=statug_genmod_examples06.htm&docsetVersi... 

 

SteveDenham

Ksharp
Super User
Agree. That is why I said " did not post the data yet "
Ksharp
Super User
One more thing,
OP said ASSOCIATION not CORRELATION , Therefore that is bring me into contingency table analysis .
SteveDenham
Jade | Level 19

Good point @Ksharp .for the categorical variables.  I guess I got caught up in the continuous side, where modeling makes some sense, even with a sample size as small as this.

 

SteveDenham

ballardw
Super User

@duckypooh wrote:

Hello! 

 

Sorry if my question seem basic but i am new to statistical analysis and would to ask which is the best test to determine association between variables and outcome if: 

 

1. I have a small sample size ~15 

2. 1 binary independent variable 

3. A mixture of continuous and categorical dependent variables 

 

TIA! 


What type of research question is to be answered? Question will point towards choice of test(s).

Are your categorical variables possibly ordinal? That means an order could be determined "Bad neutral Good" as apposed to simple category " Fred Orange XYZZY"?

 

 

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