Firstly, I'm sorry if it seems basic question. I'm stack with a simple chisq.test, I think its linked to my datas class (data.frame), even if I think that it is ok with the shape:
cat3=structure(list(`1` = c(1, 3, 0, 0, 0, 2, 0, 3, 0, 0, 1.5, 4,
0, 0, 0, 0, 0, 0, 9, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 1,
5, 0, 0, 0, 0, 0, 0.5), `2` = c(1, 0, 0, 0, 0, 2, 0, 2, 0.5,
0, 2.5, 6, 0, 0, 0, 0, 0, 0, 11.5, 1, 2, 1.5, 0, 0, 1, 0, 0,
0, 0, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 1.5), `3` = c(0, 0, 0, 0,
2.5, 2, 0, 0, 0, 0, 0, 5.5, 2, 0, 1, 0, 0, 0, 3, 1, 0, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 4, 2, 0, 0, 0, 0, 0, 3.5), `4` = c(0,
1, 0.5, 0, 0, 1, 0, 1, 0, 0, 0, 3, 1, 0, 3, 0, 0, 0, 1, 7, 0,
2, 4, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0.5, 0, 0, 3.5, 4),
`5` = c(0, 2, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1.5, 0, 2, 0,
0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 2.5, 4), `6` = c(0, 0, 0, 0, 0, 2.5, 0, 1, 0, 1,
0, 1.5, 0, 0, 3.5, 0, 0, 0, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0,
1, 0, 0, 0, 0.5, 0, 2.33333333333333, 0, 0, 0, 2, 1), `7` = c(1,
1, 1, 0, 0, 3.5, 0, 0, 0, 0, 0, 1.5, 0, 0, 1, 0, 0, 0, 0,
4, 0, 0, 0, 0, 0, 1, 0.5, 0, 0.5, 0, 1, 0, 0, 0, 3, 1, 2,
0, 1.5, 0), `8` = c(1, 0, 0, 0, 0, 1.5, 0, 0, 0, 2, 0, 1,
0, 0, 0.5, 2, 1, 0, 0, 0.5, 0, 0, 0, 0.333333333333333, 0.5,
0, 0, 0, 1.5, 0, 0, 0, 0, 0, 1.5, 1.5, 0, 0, 1, 0), `9` = c(2,
0, 0, 0, 0.5, 0.5, 0, 3.5, 0, 0, 0, 0.5, 0, 0, 0, 0, 1, 0,
0, 3, 0, 0, 0, 0, 0, 0.5, 1, 1, 2, 0, 0, 0, 0, 3, 3, 3, 0,
0, 0, 0.5), `10` = c(2, 0, 0, 0, 0, 0, 0, 2.5, 0, 0, 0, 0,
0, 0, 0, 1.5, 1.5, 1, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0.333333333333333,
7, 0, 0, 0, 0, 0, 2, 3.5, 0, 0, 0, 0), `11` = c(1, 0, 0,
0, 0, 0, 0.5, 0, 0, 0, 0, 0, 0, 0.5, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1.5, 0, 0, 0, 0, 0, 0, 0, 0, 0.333333333333333,
4.33333333333333, 0, 0, 0, 0), `12` = c(1, 0, 0, 0.5, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,
0, 7, 0, 0, 1, 0, 0, 0, 0, 0, 0, 4.5, 0, 0, 0, 0)), .Names = c("1",
"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"), class = "data.frame", row.names = c(NA,
-40L))
I'm trying to run the chisq.test(cat3) function but I have no p-value nor a X².
Pearson's Chi-squared test
data: cat3
X-squared = NaN, df = 429, p-value = NA
I found no way to transform a dataframe into a contingency table in order to use chisq.test function. Is it due to my class table ? else what is the problem, why I have no value for p and X² ?
Thanks a lot.
The problem is, you have all 0 (empty) rows in your data:
> any(rowSums(cat3) == 0)
[1] TRUE
You can delete empty rows:
> cat3_sub <- cat3[rowSums(cat3) != 0, ]
> chisq.test(cat3_sub)
Pearson's Chi-squared test
data: cat3_sub
X-squared = 731.21, df = 407, p-value < 2.2e-16
Warning message:
In chisq.test(cat3_sub) : Chi-squared approximation may be incorrect