Delta method

rainbow34

New Member
I was wondering if anybody can help me as I've been stuck on this problem for ages and my attempts seem to all be incorrect so far.

I have four estimators (W,Χ,Y,,Z) and standard errors for each. How can the standard error of D be cacluated from the following equation, where K, and L are constants?

D=W(K/(XY(Z+L)))

I believe I need to use the delta method for this also but I have no idea how to go about it.

rainbow34

New Member
Thank you. I have looked at almost every website I can find on the delta method and from what I can gather
VarXYZ=D^2.[(VarX/X^2)+(VarY/Y^2)+(VarZ/Z^2)]

But I can't work out how this changes when a constant divides XYZ.

rainbow34

New Member
Thank you. I have looked at almost every website I can find on the delta method and from what I can gather
VarXYZ=D^2.[(VarX/X^2)+(VarY/Y^2)+(VarZ/Z^2)]

But I can't work out how this changes when a constant divides XYZ.

BGM

TS Contributor
It is just following the (Multivariate) Taylor Expansion principle, expanded about the mean point. Do you find difficulties when following the wiki page?

rainbow34

New Member
It is just following the (Multivariate) Taylor Expansion principle, expanded about the mean point. Do you find difficulties when following the wiki page?
Yes my limited maths means I am really struggling with this one.