How do you analyse and obtain a p-value from a 2*2 table examining a binary outcome that is paired, when one cell has zero events? To clarify, I was looking at the success rate of obtaining an adequate image, using two different ultrasound windows, in the same participant. Then we repeated this experiment for 30 different participants. So each participant had the two views attempted, and the success rates of obtaining a good view for each attempt was recorded. So the data is paired, and our results are as follows: Success Failure View 1 30 0 View 2 26 4 My understanding is that I cannot run a Fisher’s exact test as the data is not independent. And it will not run anyways with a zero value cell. So I tried rearranging the data and running a McNemar test. View 2 Success Failure View 1 Success 26 4 Failure 0 0 But the McNemar would not run because of the zero value in cell c. I needed a p-value for these results and I’m at a loss as to what to do! I use SAS for analysis. Any pointers would be much appreciated.
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