(This note is largely in support of points made by Rich Ulrich and
Paul Swank.)
I disagree with the claim (expressed in several recent postings) that
z-tests are in general superseded by t-tests. The t-test (in simple
one-sample problems) is developed under the assumption that independent
observ
Alan:
Could you please give us an example of such a situation?
">Consider first a set of measurements taken with
>a measuring instrument whose sampling errors have a known standard
>deviation (and approximately normal distribution)."
Jon
At 01:10 PM 4/20/01 -0400, you wrote:
>(This note is lar
Alan:
I don't understand your comments about the estimation of a proportion.
It sounds to me as if you are using the estimated standard error. (Surely
you are not assuming a known standard error.) You are presumably, also
using the normal approximation to the binomial (or perhaps the
hypergeometr
I agree. ANCOVA is often said to be used when the groups are not experimental. It is a linear model of the same nature as ACOVA but technically ANCOVA refers to the experimental situation. The general linear model would allow comparing the groups while controlling for X but as William says, you sho
