Comparing row proportions from an individual column of a Chi- sq test for significance?

[supreets89]

Hi Everyone,

How can I test for significance using proportions in the following data:

Var                 X       Y     Z 

                A   50      60     10

                B   100   200    300    

If i want to show that the total proportion of Z in A (10/120)  is different from Z in B (300 /600), which test of significance would I use and how would i code it? My data is structured the following way:
v1    v2    v3
A      X     50
A      Y     60
A      Z     10
B      X    100

B      Y     200

B      Z     300

I know Chi-sq would compare proportions in all three columns together, but how can i focus the significance test to just Z in A vs Z in B.

[PaigeMiller]

You could compare the two proportions using the formula here:

https://onlinecourses.science.psu.edu/stat500/node/55

just underneath the heading "Hypothesis Testing to Compare Two Population Proportions: p1,p2" (this assumes that groups A and B are independent, statistically)

You could use PROC FREQ to obtain the proportions, and then the formula itself isn't hard to program in a data step.

[StatDave]

All you care about is Z and not Z - the separate X and Y levels can be combined. PROC FREQ can do the chi-square test for you:

data a;
input r $ c $ count;
datalines;
A notZ 110
A Z     10
B notZ 300
B Z    300
;
proc freq;
table r*c / chisq;
weight count; 
run;

[Ksharp]

Or you want do Trend Analysis ?

proc freq;

table v1*v2/trend;

run;

[sld]

I think that the solution suggested by @SAS_Rob in this current Community thread Chi square test of association which links to this note http://support.sas.com/kb/22/565.html would provide you with the tools you need.