About JanetSultana

StatDave · ‎10-03-2018

Your trend analysis in PROC FREQ is not correct since it doesn't use the actual sample sizes. The following code uses the observed sample sizes. Because your sample sizes are so large, there is no need for an exact test. data test; input year case n; w=case; y=1; output; w=n-case; y=0; output; datalines; 2000 100 50000 2005 75 60000 2010 50 75000 ; proc freq; weight w; table year*y/trend; run; A similar analysis can be done in PROC GENMOD or PROC LOGISTIC as I mentioned. Note that the square root of the Score chi-square is the same as the Cochran-Armitage statistic in PROC FREQ. proc logistic; freq w; model y(event="1")=year; run;

JanetSultana · ‎03-23-2016

Thank you very much for your reply- its exactly what I needed! I do have some final questions about how to interpret the output: I imagine that I have to use the results from the Likelihood Ratio Chi-Square rather than the Chi-Square since I’m interested in the ratios, correct? (Although they were really similar) The default null hypothesis is be that there is no significant difference between the ratios, right? SAS warns me that 63% of my data is missing- this would make sense because of the unequal sample sizes. I wonder if this is a problem as far as the reliability of the results are concerned or how cautious I should be in interpreting the results? Thanks again for your quick reply, I learned something new which I can apply elsewhere !! 🙂

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Date Last Visited	‎10-04-2018 09:18 AM

Re: Is it correct to use proc genmod when testing for trends?

Is it correct to use proc genmod when testing for trends?

Re: Chi squared test for unequal sample sizes

Chi squared test for unequal sample sizes

Re: Is it correct to use proc genmod when testing for trends?

Re: Chi squared test for unequal sample sizes