> lm(Female ~ Male, data = too.young) Call: lm(formula = Female ~ Male, data = too.young) Coefficients: (Intercept) Male 5.472 0.575 > plot(Female ~ Male, data = too.young) > abline(lm(Female ~ Male, data = too.young)) > abline(7,1/2,lwd=2)The result from the data set is a little more conservative than the rule of thumb, except for the teenage years.