r:chi-square_test:output01
> # install.packages("MASS")
> library(MASS)
>
> print(str(survey))
'data.frame': 237 obs. of 12 variables:
$ Sex : Factor w/ 2 levels "Female","Male": 1 2 2 2 2 1 2 1 2 2 ...
$ Wr.Hnd: num 18.5 19.5 18 18.8 20 18 17.7 17 20 18.5 ...
$ NW.Hnd: num 18 20.5 13.3 18.9 20 17.7 17.7 17.3 19.5 18.5 ...
$ W.Hnd : Factor w/ 2 levels "Left","Right": 2 1 2 2 2 2 2 2 2 2 ...
$ Fold : Factor w/ 3 levels "L on R","Neither",..: 3 3 1 3 2 1 1 3 3 3 ...
$ Pulse : int 92 104 87 NA 35 64 83 74 72 90 ...
$ Clap : Factor w/ 3 levels "Left","Neither",..: 1 1 2 2 3 3 3 3 3 3 ...
$ Exer : Factor w/ 3 levels "Freq","None",..: 3 2 2 2 3 3 1 1 3 3 ...
$ Smoke : Factor w/ 4 levels "Heavy","Never",..: 2 4 3 2 2 2 2 2 2 2 ...
$ Height: num 173 178 NA 160 165 ...
$ M.I : Factor w/ 2 levels "Imperial","Metric": 2 1 NA 2 2 1 1 2 2 2 ...
$ Age : num 18.2 17.6 16.9 20.3 23.7 ...
NULL
> ??MASS::survevy
>
> wh.clap = data.frame(survey$Clap,survey$W.Hnd)
> wh.clap.tbl = table(survey$Clap,survey$W.Hnd)
> wh.clap.tbl
Left Right
Left 9 29
Neither 5 45
Right 4 143
> chisq <- chisq.test(wh.clap.tbl)
경고메시지(들):
chisq.test(wh.clap.tbl)에서:
카이제곱 approximation은 정확하지 않을수도 있습니다
> chisq
Pearson's Chi-squared test
data: wh.clap.tbl
X-squared = 19.252, df = 2, p-value = 6.598e-05
> o <- chisq$observed
> e <- chisq$expected
> o
Left Right
Left 9 29
Neither 5 45
Right 4 143
> round(e, 2)
Left Right
Left 2.91 35.09
Neither 3.83 46.17
Right 11.26 135.74
> res <- (e-o)/sqrt(e)
> round(res,2)
Left Right
Left -3.57 1.03
Neither -0.60 0.17
Right 2.16 -0.62
> chisq.cal <- sum(res^2)
> p.val <- pchisq(chisq.cal, df=2, lower.tail = F)
> chisq.cal
[1] 19.25239
> p.val
[1] 6.597765e-05
> chisq
Pearson's Chi-squared test
data: wh.clap.tbl
X-squared = 19.252, df = 2, p-value = 6.598e-05
>
> barplot(wh.clap.tbl, beside = TRUE,
+ col = c("red", "lightgreen", "blue"),
+ main = "wh vs ex",
+ xlab = "Exercise Level", ylab = "Number of Students")
>
> legend("center", legend = rownames(wh.clap.tbl),
+ fill = c("red", "lightgreen" ,"blue"))
>
>
r/chi-square_test/output01.txt · Last modified: by hkimscil