On 26 Mar 2003 at 10:55, Rich Ulrich wrote: > On Wed, 26 Mar 2003 13:18:17 +0100, "david" <[EMAIL PROTECTED]> wrote: > > > Hello > > I would like to know a measure for testing the binormality of a data set. > > thanks in advanced > > I don't use the term, binormal. > And Google turns up something concerning topology, > which is not a usual topic in these groups. > > Are you referring to bivariate normality?
What is the wromg with the word binormal? > > If so -- the straight, simple approach, to start, is > to test the variables separately, and combine tests, > preserving power or alpha, depending on which matters > to you. > > Bivariate normality implies that the linear combinations > of the two should also be normal. The obvious > combinations are the principal components: form > them and test them; and combine tests. Could it be an idea here to look into exploratory projection pursuit, which is often looking for the least normal linear conbination? Kjetil Halvorsen > > There are various tests for 'normality.' > How the data are generated could suggest the fashion > in which non-normality is apt to arise. If the variables > are two versions of the same measurement, there > might be special salience to simple difference score. > > If you have a particular need -- symmetry, continuity > (lack of ties), absence of outliers, presence of > exponential tails, infinite theoretical range -- > you should select or design a test to meet that need. > > If you have a particular reason to suspect deviations > that you can characterize -- and they matter -- you > should test for those deviations. > > - "goodness of fit" depends on what aspects you > want to fit, so there is never a single test for something > like "normality." > > Hope this helps. > -- > Rich Ulrich, [EMAIL PROTECTED] > http://www.pitt.edu/~wpilib/index.html > . > . > ================================================================= > Instructions for joining and leaving this list, remarks about the > problem of INAPPROPRIATE MESSAGES, and archives are available at: > . http://jse.stat.ncsu.edu/ . > ================================================================= . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
