Kurskal-Wallis Test for the One-Way Layout

line <- rep(1:3,rep(10,3))
defects <- c(6,38,3,17,11,30,15,16,25,5,34,28,42,13,40,31,9,32,39,27,13,35,19,4,29,0,7,33,18,24)

R <- rank(defects)

defect <- data.frame(line, defects, R)

# rank sum of each group
S <- tapply(defect$R,defect$line,sum)

# sample size of each group
ni <- table(defect$line)

# total sample size
n <- sum(ni)

# number of groups
k <- length(unique(line))

# test statistic
H <- 12/(n*(n+1))*sum(S^2/ni) - 3*(n+1)

# p-value
pvalue <- 1-pchisq(H, k-1)

### R function
kruskal.test(defects~line, data=defect)