Scatter Plot

[Wilhellmuss Mauka]

What command can I use to create a Scatter plot with regression line and line of perfect correlation?

[Nick Cox]

What's the line of perfect correlation? If y = 1 trillion + 1 quadrillion x exactly the correlation would also be 1. There's an infinity of rising straight lines that would yield a correlation of 1 and an infinity of falling straight lines that would yield a correlation of -1.

Do you mean the line of equality y = x?

[Wilhellmuss Mauka]

1:1

[Wilhellmuss Mauka]

Yes Nick, y=x

[Nick Cox]

OK. I'd call that the line of perfect agreement or the line of equality.

Here is some technique. The example isn't serious. See also aaplot from SSC.

sysuse citytemp, clear 

set scheme s1color 

scatter tempjul tempjan, ms(Oh) ///
|| lfit tempjul tempjan         ///
|| function Equality=x, ra(tempjan) lp(dash) ///
legend(order(2 3) col(1) ring(0) pos(5)) ///
ytitle("`: var label tempjul' ({&degree}F)") /// 
xtitle("`: var label tempjan' ({&degree}F)") ///
xsc(titlegap(*5)) aspect(1) yla(, ang(h))

[Wilhellmuss Mauka]

Thanks very much, Nick
it has worked perfectly!