[R] formula (joint, conditional independence, etc.) - mosaicplots

[David Meyer]

On 2003.06.13 02:11, g wrote:
> Hi,
> 
> Can someone set me straight as to how to write formulas in R to
> indicate:
> 	complete independence [A][B][C]

Freq ~ A + B + C

> 	joint independence [AB][C]

Freq ~ A * B + C

> 	conditional independence [AC][BC]

Freq ~ A * C + B * C

> 	nway interaction [AB][AC][BC]

Freq ~ A * B * C - A:B:C


You might have a look at demo(mosaic) in package vcd.

g.,
-d


> ?
> 
> 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
> 
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