RG #3: multiple scatter plot with smoothed line (trellis plots)

# data 

set.seed (12345)

y1 <- rnorm(1000, 12,9)

x1 <- 0.35 *y1 + rnorm(1000, 0,3)

x2 <-  c(rep("A",500), rep("B",500))

x3 <-  c(rep(1,100), rep(2,100), rep(3,100), rep(4,100), rep(5, 100), rep(1,100), rep(2,100), rep(3,100), rep(4,100), rep(5, 100))

data2 <- data.frame(x1, y1, x2, x3)

require(ggplot2) 

# scatter plots with out lines 

qplot(y1, x1, data =data2) + facet_grid(x2 ~ x3)+theme_bw()

# with smoothed lines  

qplot(y1, x1, data =data2, geom = c("point", "smooth"), method = "lm") + facet_grid(x2 ~ x3)+ theme_bw()