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Also they say they used the Fisher exact test and got a p value for mortality of 0.09 so it seems they were doing a two-sided test which is the default for fish
by ggrothendieck 5y ago
Also they say they used the Fisher exact test and got a p value for mortality of 0.09 so it seems they were doing a two-sided test which is the default for fisher.test in R.
ivm <- c(3, 247-3)
con <- c(10, 249-10)
m <- rbind(ivm, con)
fisher.test(m)$p.value
## [1] 0.08809225
However, I think a one sided test could be justified and in that case it is significant at the 5% level.
fisher.test(m, alternative = "less")$p.value
## ivm
## 0.04541928
- s1artibartfast 5y agoOut of curiosity, which fisher test was used for the other endpoints?
- ggrothendieck 5y agoThe Mech Vent and ICU also used two sided tests.
- ggrothendieck 5y agoFurthermore a test just twice as large would be sufficient to determine significance at the 1% level even with a two sided test if the same death rate continued to hold. ivm <- c(3, 247-3) con <- c(10, 249-10) m <- rbind(ivm, con) fisher.test(2*m)$p.value # 2* so that it is twice as large ## [1] 0.008490957