#simple hsked plot
set.seed(127)
x<-seq(1,200,1)
y<-3.8*x+25+err
err<-NULL
for(i in c(1:200)) {
	err[i]<-rnorm(1,0,i)
	}
y<-3.8*x+25+err;
plot(y~x,pch=20,main="Random Data with First-Order Heteroskedastic Errors")
abline(coef=lm(y~x)$coefficients,col=3)
legend(15,900,col=c(1,3),legend=c("Data Points","Linear Regression"),fill=c(1,3));
text(100,991,labels="Adj.",col=3)
text(110,1000,labels=expression(R^2),col=3)
text(116,995,labels="=",col=3)
text(128,995,labels=signif(summary(naivelm)$adj.r.squared,digits=4),col=3);