#1a
y=c(2.2, 1.3, 4.2, 2.4, 3.0, 1.1)

#1b
A = c("a1", "a1"," a2", "a2", "a3", "a3")
B = c("b1", "b2"," b1", "b2", "b1", " b2")

#1c
z1 = data.frame(A,B, y)

#1d
by(z1[,3], A, mean)

#2a
x<-matrix(c(3.42, 5.223, 10.8745,7.53, 4.435, 2.634, 3.21, 8.677, 2.7634),nrow = 3, ncol=3)
x1<-round(x, digits=1)

#2b
x2<-10*x1
#2c
x3<-t(x2)

#2d
v1<-x3[,1]
v2<-x3[1,]
#2e
Y <-cbind(v1, v2)
Y<-t(Y)
Y
#2g
x4<-apply(x3, c(2), sort)
x4