# Aufgabe 4
n <- 10
data <- read.table("C:/Lehre/Wirtschaftsstatistik2012/Blatt5/matphys.txt", header = TRUE)

# a)
plot(data$Mathematik, data$Physik, xlab = "Mathe-Note", ylab = "Physik-Note")

# b)
modell1 <- lm(data$Physik ~ data$Mathematik)
modell1$coefficients
abline(modell1$coefficients[1], modell1$coefficients[2], lwd = 2)

# c)
modell2 <- lm(data$Mathematik ~ data$Physik)
modell2$coefficients
abline(- modell2$coefficients[1] / modell2$coefficients[2], 1 / modell2$coefficients[2], lwd = 2, lty = 2)
legend(x = 65, y = 95, legend = c("b)", "c)"), lty = c(1, 2), lwd = c(2, 2))

# d)
summary(modell1)
summary(modell2)