Need help reversing a formula...

[Larry Webb]

Ok, I'll admit it right now.
I don't have as many brain cells as I used to and I need help.

I have the following formula in Excel and I'm trying to reverse it....

Answer =NORMSINV(1-X/2)*Y/SQRT(Z)

At the Microsoft support site it says this returns the same value as
Answer =CONFIDENCE(X,Y,Z)
and indeed it does.

I have the value for Answer, and the values of X and Y.

What formula do I need to get the value of Z?


Thanks in advance.

I'm going to take some aspirin now...


Larry W.
Las Vegas, NV

 

[Rob Bovey]

Hi Larry,

My statistics are pretty rusty, so I have no idea if this is
meaningful, but solving for Z algebraically gives you:

Z = (NORMSINV(1-X/2)*Y/Answer)^2

--
Rob Bovey, Excel MVP
Application Professionals
http://www.appspro.com/

* Take your Excel development skills to the next level.
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http://www.appspro.com/Books/Books.htm

 

[Larry Webb]

Hi Larry,

My statistics are pretty rusty, so I have no idea if this is
meaningful, but solving for Z algebraically gives you:

Z = (NORMSINV(1-X/2)*Y/Answer)^2

Yeah, that's it. Don't know why I couldn't see that for myself.

Too few brain cells left and not enough sleep I guess.

Thanks!


Larry