x<-seq(from=-5,to=5,by=0.01);
plot(x,dnorm(x),main="N(m,1)",xlab="Wartość",ylab="y")
lines(x,dnorm(x*2),type="p",col="blue")
lines(x,dnorm(x/2),type="p",col="red")
legend("topright",c("N(0,1)","N(0,4)","N(0,1/4)"),col = c("black","red","blue"), pch = c(1));