[R] data analysis for partial two-by-two factorial design

[Ding, Yuan Chun]

Hi Bert,

I am very sorry to bother you again.

For the following question, as you suggested, I posted it in both Biostars website and stackexchange website, so far no reply.

I really hope that you can do me a great favor to share your points about how to explain the coefficients for drug A and drug B if run anova model (response variable = drug A + drug B). is it different from running three separate T tests?

Thank you so much!!

Ding

I need to analyze data generated from a partial two-by-two factorial design: two levels for drug A (yes, no), two levels for drug B (yes, no);  however, data points are available only for three groups, no drugA/no drugB, yes drugA/no drugB, yes drugA/yes drug B, omitting the fourth group of no drugA/yes drugB.  I think we can not investigate interaction between drug A and drug B, can I still run  model using R as usual:  response variable = drug A + drug B?  any suggestion is appreciated.


From: Bert Gunter [mailto:bgunter.4567 at gmail.com]
Sent: Friday, March 02, 2018 12:32 PM
To: Ding, Yuan Chun
Cc: r-help at r-project.org
Subject: Re: [R] data analysis for partial two-by-two factorial design

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This list provides help on R programming (see the posting guide linked below for details on what is/is not considered on topic), and generally avoids discussion of purely statistical issues, which is what your query appears to be. The simple answer is yes, you can fit the model as described,  but you clearly need the off topic discussion as to what it does or does not mean. For that, you might try the stats.stackexchange.com<http://stats.stackexchange.com> statistical site.

Cheers,
Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Fri, Mar 2, 2018 at 10:34 AM, Ding, Yuan Chun <ycding at coh.org<mailto:ycding at coh.org>> wrote:
Dear R users,

I need to analyze data generated from a partial two-by-two factorial design: two levels for drug A (yes, no), two levels for drug B (yes, no);  however, data points are available only for three groups, no drugA/no drugB, yes drugA/no drugB, yes drugA/yes drug B, omitting the fourth group of no drugA/yes drugB.  I think we can not investigate interaction between drug A and drug B, can I still run  model using R as usual:  response variable = drug A + drug B?  any suggestion is appreciated.

Thank you very much!

Yuan Chun Ding


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