2 x 2 chisq.test (PR#8415)

Full_Name: nobody
Version: 2.2.0
OS: any
Submission from: (NULL) (219.66.34.183)


2 x 2 table, such as

x

    [,1] [,2]
[1,]   10   12
[2,]   11   13

chisq.test(x)

	Pearson's Chi-squared test with Yates'
	continuity correction

data:  x
X-squared = 0.0732, df = 1, p-value = 0.7868

but, X-squared = 0.0732 is over corrected.

when abs(a*d-b*c) <= sum(a,b,c,d), chisq.value must be 0!, and P-value must be
1!

code of chisq.test must be as follows

#           if (correct && nrow(x) == 2 && ncol(x) == 2) {
#               YATES <- 0.5
#               METHOD <- paste(METHOD, "with Yates' continuity correction")
#           }
#           else YATES <- 0
#           STATISTIC <- sum((abs(x - E) - YATES)^2/E)
## replace begin
            if (correct && nrow(x) == 2 && ncol(x) == 2) {
                STATISTIC <- if (abs(x[1,1]*x[2,2]-x[1,2]*x[2,1]) < sum(x)/2) 0

                             else sum((abs(x - E) - 0.5)^2/E)
                METHOD <- paste(METHOD, "with Yates' continuity correction")
            }
            else STATISTIC <- sum((abs(x - E))^2/E)
## replace end