卡方检验误差 "Chi-squared approximation may be incorrect"

Question

我运行在 R 中进行卡方检验，结果是：

crianza = matrix(c(1,1,0,12,12,7,2,1,0,0,1,0,0,0,5,
      0,0,0,1,1,2,0,0,3,0,0,0,13,35,29,0,0,1,10,
      0,0,1,0,0,0,0,0),ncol=3,byrow=TRUE)
colnames (crianza) = c("Neonate","Juevenile","Adult")
rownames (crianza) = c("C.acronotus","C.limbatus","C.obscurus","C.perezi",
 "C.porosus","C.falciformis","G.cuvier","G.cirratum","M.canis",
 "R.porosus","R.lalandii","S.lewini","S.mokarran","S.tiburo")    
crianza = as.table(crianza)

Pearson's Chi-squared test

data:  crianza
X-squared = NaN, df = 26, p-value = NA

Warning message:
In chisq.test(crianza) : Chi-squared approximation may be incorrect

有谁知道为什么会发出警告？是不是我用错方法了？

Answer 1

您得到 NA 个值，因为您的行根本没有计数。

cc <- crianza[rowSums(crianza)>0,]
chisq.test(cc)

要避开警告，请尝试 simulate.p.value=TRUE:

chisq.test(cc, simulate.p.value=TRUE)

请注意，这是一个极度不平衡的 table，使用模拟的 p 值，您基本上会得到一个小至 1/（模拟次数运行）的值：

chisq.test(cc, simulate.p.value=TRUE, B=1e6)

在我运行失去耐心之前，我达到了 B=1e7。您可能不必担心超出 "the p-value is very small, at most 1e-6"

的报告值

卡方检验误差 "Chi-squared approximation may be incorrect"

Chi square test error "Chi-squared approximation may be incorrect"

r

chi-squared