On Mon, 10 Dec 2001 12:57:29 -0400, Gus Gassmann <[EMAIL PROTECTED]> wrote:
> Art Kendall wrote: > > (putting below the previous quotes for readability) > > > Gus Gassmann wrote: > > > > > Dennis Roberts wrote: > > > > > > > this is pure speculation ... i have yet to hear of any convincing case > > > > where the variance is known but, the mean is not > > > > > > What about that other application used so prominently in texts of > > > business statistics, testing for a proportion? > > > the sample mean of the dichotomous (one_zero, dummy) variable is known, It > > is the proportion. GG > > Sure. But when you test Ho: p = p0, you know (or pretend to know) the > population variance. So if the CLT applies, you should use a z-table, no? > That is the textbook justification for chi-squared and z tests in the sets of 'nonparametric tests' which are based on rank-order transformations and dichotomizing. The variance is known, so the test statistic has the shorter tails. (It works for ranks when you don't have ties.) -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================
