Quadratic Function

[Taiba Chau]

Hi, I am trying to create a quadratic function in Stata. I have tried a few things but nothing seems to work. An error message appears.I have a few other variables within my regression so I am not sure if that's the reason as to why it isn't working. So far I have tried:

twoway (function y=-0.45+0.17*x-0.11x^2+0.075*g+0.095*h+0.16*j, range(0 10))

Then I tried implying it to:

twoway (function y=-0.45+0.17*x-0.11x^2, range(0 10))

Any thoughts?

[Ken Chui]

Missing an asterisk (*)

[Rich Goldstein]

the range only applies to "x" so Stata is confused by your first statement

your second statement has a typo - insert "*" between the "11" and the "x^2" (as you have between the "17" and the "x"

[Nick Cox]

To add to earlier replies:

With nothing else said

y=-0.45+0.17*x-0.11x^2+0.075*g+0.095*h+0.16*j,

defines y in a space with (x, g, h, j) as other coordinates. What are you expecting to be the result graohically?

[Jared Greathouse]

This would result in a 4D plane.

You'd need to choose some values for two of your variables. Even if Stata could make this, (which I could never imagine StataCorp investing the time and money in) trust me, you wouldn't wanna be tasked with reading it and understanding the figure that this would produce