TI-89 Titanium Residual Plot Question

[T0NY]

When I go into plot setup and type:

x= list 2 (the x-axis)
y= resid

then I press plot and it says "Undefined Variable"

How would I fix this??

Any help will be appretiated
Thank You

[linle]

for y press 2nd varlink and find resid. hope it works.