Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: nomogram
Replies: 1   Last Post: Jul 12, 2006 9:43 AM

 Old Mac User Posts: 104 Registered: 3/12/06
Re: nomogram
Posted: Jul 12, 2006 9:43 AM

No, we do not "always use beta = 0.1.

Question:

Are you doing this work stirctly around the matter of testing whether
there is a "real difference" between two averages? Something that
would eventually lead to a Student t-test? If so, there's a simple
equation for estimating the proper sample size for a particular choice
of alpha and beta. OMU

Natalie Vivien wrote:
> Hi everyone!
>
> I am assigned a school project to design a clinical trial. I was told
> to calculate power. I remember power is the probability of rejecting Ho
> when Ho is false which is 1-beta. Do we always use beta=0.1? I read
> this up in a statistical book.
>
> If so, how do we use the nomogram to look for the corresponding sample
> size? The chart is the one which has two scales by the sides (one for
> difference and one for power) and a straight line in the middle with a
> decreasing gradient (indicating the sample size)?
>
> Hope someone can help me if not I will be stuck in the initial stage. :)