Re: Confidence Limit

"Dirk Van de moortel" <[EMAIL PROTECTED]> wrote
in message news:[EMAIL PROTECTED]
>
> from which you can easily algebrate and calculate mu1 and mu2 ;-)

Thanks for the answer. I've worked out how to do most of it, and I have an
equation to use.

The equation is CL (lower) = xbar - z(st.dev/sample size)

It have applied it fine in case where z has been supplied. What I need to
know though is how do I get the value of z? 'z' is defined as "the (Normal)
value such that P(-z < Z < z) = CL.

I have no clue how to get it - I tried to get it via the Inverse General
Normal table but I couldn't match the value that was supplied to me.

e.g. Confidence Level 0.90 then z = 1.645