pdf("trombone.pdf")

trombone1 <- read.fwf("C:\\data\\trombone.dat", width=c(8,8,8,8,8,8,8,8,8,8,8),
col.names=c("trt", "x", "y","pp","mp","cp","mps","ppx","mpx","cpx","mpsx"))

attach(trombone1)

trt <- factor(trt, levels=1:5,
labels=c("pp", "mp", "cp", "mps","control"))


tapply(y, trt, mean) # marginal mean for y
tapply(x, trt, mean) # marginal mean for x

mean(x)

# Fit Model with Interaction 
trombone1.aov <- lm(y ~ x + pp + mp + cp + mps + ppx + mpx + cpx +mpsx)

summary(trombone1.aov)

# Fit Model without Interaction 
trombone2.aov <- lm(y ~ x + pp + mp + cp + mps)

summary(trombone2.aov)

# Fit Model without treatment effects
trombone3.aov <- lm(y ~ x)

summary(trombone3.aov)


dev.off()