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SAS_Chi SQUARE_Compare two percentages

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Contributor
Posts: 53

SAS_Chi SQUARE_Compare two percentages

Hi all,

 

I want to compare two percentages. I think Chi-Square test is appropriate for this. So, I have the following datasets;

 

Group    Number of Success         Total number

1                   5                                     10

2                   4                                      30

 

I need to compute the percantages of number of success in the first and second group and then compare them whether the difference between this comparision is statistically significant by using Chi-Square test. So the should be one more column:

 

Group    Number of Success         Total number            Percentages

1                   5                                     10                              50%   (5/10*100)

2                   3                                      30                             10%   (3/30*100)

 

And then I want to see whether the difference between percantages (50% and 10%) is statistically significant by using Chi-Square test. 

 

 

Super User
Posts: 19,791

Re: SAS_Chi SQUARE_Compare two percentages

Posted in reply to Khaladdin

Chi Square would use the raw numbers from the 2x2 table, not the percentages. 

 

To compare percentages you can use PROC TTEST but you need to make sure to include the correct N and possibly the standard deviation. You also need to factor in a continuity correction.

 

I recommend PROC FREQ instead of trying to test the percentages. The data lends itself to that format naturally. 

Contributor
Posts: 53

Re: SAS_Chi SQUARE_Compare two percentages

Posted in reply to Khaladdin
Dear Reeza,

Many thanks for reply. Could you please explain how to use PROC FREQ? could you please give me the sample codes?
Trusted Advisor
Posts: 1,917

Re: SAS_Chi SQUARE_Compare two percentages

Posted in reply to Khaladdin

An example showing how to use PROC FREQ to compare two proportions is:

http://support.sas.com/kb/22/561.html

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