# Difference in proportions but one of them is 0

What is the best way to test for difference of proportions when of them is 0% (or 100%) ?

edit: I have two raters, who give a score of either 1 or 0. One of them gave a 0 in every single case. Now I want to know if the proportions of 1's is significantly different between the two.

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Yes, I just did so. –  blues Sep 15 '12 at 14:42
I think you are refrerring to the sample proportion and not the population proportion. The case of sample proportion equal 0 does not create problems unless you try to use normal or chi-square approximation. You can apply Fisher's exact test for differences in proportions or apply the Kappa statistic to test interrater agreement. –  Michael Chernick Sep 15 '12 at 14:57
If this was an answer and not a comment I would/could accept it. –  blues Sep 15 '12 at 15:00

Since you are referring to the sample proportion and not the population proportion. The case of sample proportion equal 0 does not create problems unless you try to use normal or chi-square approximations. You can apply Fisher's exact test for differences in proportions or apply the Kappa statistic to test interrater agreement

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