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