# install.packages("MASS")
library(MASS)     

print(str(survey))
??MASS::survevy

wh.clap = data.frame(survey$Clap,survey$W.Hnd)
wh.clap.tbl = table(survey$Clap,survey$W.Hnd) 
wh.clap.tbl
chisq <- chisq.test(wh.clap.tbl)
chisq
o <- chisq$observed
e <- chisq$expected
o
round(e, 2)
res <- (e-o)/sqrt(e)
round(res,2)
chisq.cal <- sum(res^2)
p.val <- pchisq(chisq.cal, df=2, lower.tail = F)
chisq.cal
p.val
chisq

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"))