Message-ID: <200306130111.33130.gina.joue@ucd.ie>
Date: 2003-06-13T00:11:33Z
From: g
Subject: formula (joint, conditional independence, etc.) - mosaicplots
Hi,
Can someone set me straight as to how to write formulas in R to indicate:
complete independence [A][B][C]
joint independence [AB][C]
conditional independence [AC][BC]
nway interaction [AB][AC][BC]
?
For example, if I have 4 factors:
hair colour, eye colour, age, sex
does
> mosaicplot( frequency ~ hair + eye + age + sex)
mean that the model fitted is of complete independence of all factors
[hair][eye][age][sex]?
So does
> mosaicplot(frequency ~ hair + eye)
mean that the model is of conditional independence
[hairAgeSex][eyeAgeSex]?
How does the operator * as in
> mosaicplot( frequency ~ hair * eye)
or
> mosaicplot( frequency ~ hair * eye + age)
equate to in the type of independence model used?
Thanks in advance for any elucidation!
Gina