topic Re: SAS_Chi SQUARE_Compare two percentages in All Things Community

SAS_Chi SQUARE_Compare two percentages

Khaladdin — Wed, 12 Apr 2017 15:02:20 GMT

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.

Re: SAS_Chi SQUARE_Compare two percentages

Reeza — Wed, 12 Apr 2017 17:48:17 GMT

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.

Re: SAS_Chi SQUARE_Compare two percentages

Khaladdin — Wed, 12 Apr 2017 17:53:08 GMT

Dear Reeza,

Many thanks for reply. Could you please explain how to use PROC FREQ? could you please give me the sample codes?

Re: SAS_Chi SQUARE_Compare two percentages

PaigeMiller — Wed, 12 Apr 2017 18:10:00 GMT

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

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