[R] What are Type II or III contrast? (contrast() in contrast package)

David Winsemius dwinsemius at comcast.net
Wed Feb 3 06:01:20 CET 2010

On Feb 2, 2010, at 11:38 PM, Peng Yu wrote:

> ?contrast in the contrast package gives me the following description.
> However, I have no idea what Type II and III contrasts are. Could
> somebody explain it to me? And what does 'type' mean here?
>    *‘type’*: set ‘type="average"’ to average the individual contrasts
>    (e.g., to obtain a Type II or III contrast)

In no particular order:

Don't expect any follow-up questions to be answered or further  
citations offered. This is really more in the realm of statistics  
education than an R specific question.


David Winsemius, MD
Heritage Laboratories
West Hartford, CT

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