## setup framework for blocks and treatments
Chemical_type<-c(rep("1",4),rep("2",4),rep("3",4),rep("4",4))
Bolt<-c(rep(c("O1","O2","O3","O4"),4))
##Assign data to variable "strength"
strength<-c(73,68,71,67,73,67,72,70,75,68,73,68,73,71,75,69)
y<-data.frame(Chemical_type,Bolt,strength)
matrix(y$Bolt,4,byrow = T)
matrix(y$strength,4,4,byrow = T)
## Apply a linear model
yfit<-lm(strength~Bolt+Chemical_type,y)
## Compute the analysis of variance table
anova(yfit)