R help - Mar 2018 - data analysis for partial two-by-two factorial design

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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This message (and any attachments) are intended solely f...{{dropped:28}}

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
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>
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
>
>
> ---------------------------------------------------------------------
> -SECURITY/CONFIDENTIALITY WARNING-
> This message (and any attachments) are intended solely...{{dropped:13}}

Hi Bert,

Thank  you so much for your direction, I have asked a question on stackexchange
website.

Ding

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

________________________________
[Attention: This email came from an external source. Do not open attachments or
click on links from unknown senders or unexpected emails.]
________________________________

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


---------------------------------------------------------------------
-SECURITY/CONFIDENTIALITY WARNING-
This message (and any attachments) are intended solely f...{{dropped:28}}

______________________________________________
R-help at r-project.org<mailto:R-help at r-project.org> mailing list -- To
UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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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

________________________________
[Attention: This email came from an external source. Do not open attachments or
click on links from unknown senders or unexpected emails.]
________________________________

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


---------------------------------------------------------------------
-SECURITY/CONFIDENTIALITY WARNING-
This message (and any attachments) are intended solely f...{{dropped:28}}

______________________________________________
R-help at r-project.org<mailto:R-help at r-project.org> mailing list -- To
UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


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