Re: [R] a quick question about "rbinom"
On Jan 5, 2012, at 12:56 AM, Bert Gunter wrote:
David!
...
It means the author either doesn't know the 'sample' function, or
wants you
to understand how to use 'rbinom', or that's just the way she thinks.
Could someone help? Thanks so much,
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
C.f.
X1<-sample( c("A","B"), n, prob= c(0.6, 0.4))
X2<-sample( c("C","D"), n, prob= c(0.6 ,0.4))
... are wrong for n>1 !
e.g.
X1<-sample( c("A","B"), 5, prob= c(0.6, 0.4))
Error in sample(c("A", "B"), 5, prob = c(0.6, 0.4)) :
cannot take a sample larger than the population when 'replace =
FALSE'
The perils of untested code. Thanks, Bert.
## You need to add the replace=TRUE argument
X1<-sample( c("A","B"), 5, prob= c(0.6, 0.4),replace=TRUE)
X1
[1] "A" "A" "B" "A" "B"
Cheers,
Bert
It mean index the vector as 1's and 2's (1st and 2nd item in list)
rather than 0's and 1's because R indices start at 1, not 0.
Sorry for the blank message.
--
David Winsemius, MD
West Hartford, CT
__
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--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
David Winsemius, MD
West Hartford, CT
__
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Re: [R] a quick question about "rbinom"
David!
...
>
> It means the author either doesn't know the 'sample' function, or wants you
> to understand how to use 'rbinom', or that's just the way she thinks.
>
>>> Could someone help? Thanks so much,
>>>
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
>
>
> C.f.
>
> X1<-sample( c("A","B"), n, prob= c(0.6, 0.4))
> X2<-sample( c("C","D"), n, prob= c(0.6 ,0.4))
... are wrong for n>1 !
e.g.
> X1<-sample( c("A","B"), 5, prob= c(0.6, 0.4))
Error in sample(c("A", "B"), 5, prob = c(0.6, 0.4)) :
cannot take a sample larger than the population when 'replace = FALSE'
## You need to add the replace=TRUE argument
> X1<-sample( c("A","B"), 5, prob= c(0.6, 0.4),replace=TRUE)
> X1
[1] "A" "A" "B" "A" "B"
Cheers,
Bert
>
>>>
>>> It mean index the vector as 1's and 2's (1st and 2nd item in list)
>>> rather than 0's and 1's because R indices start at 1, not 0.
>>
>>
> Sorry for the blank message.
> --
>
> David Winsemius, MD
> West Hartford, CT
>
> __
> R-help@r-project.org mailing list
> 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.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
__
R-help@r-project.org mailing list
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.
Re: [R] a quick question about "rbinom"
On Jan 4, 2012, at 8:46 PM, David Winsemius wrote:
On Jan 4, 2012, at 7:43 PM, Robert Baer wrote:
-Original Message- From: lynn.tsai
Sent: Wednesday, January 04, 2012 3:38 PM
To: r-help@r-project.org
Subject: [R] a quick question about "rbinom"
Hello, I have the following code using rbinom, but I don't
understand what
*"+1"* means in the code.
It means the author either doesn't know the 'sample' function, or
wants you to understand how to use 'rbinom', or that's just the way
she thinks.
Could someone help? Thanks so much,
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
C.f.
X1<-sample( c("A","B"), n, prob= c(0.6, 0.4))
X2<-sample( c("C","D"), n, prob= c(0.6 ,0.4))
It mean index the vector as 1's and 2's (1st and 2nd item in list)
rather than 0's and 1's because R indices start at 1, not 0.
Sorry for the blank message.
--
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
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.
Re: [R] a quick question about "rbinom"
Hi, thank you all for replying. First, it's not a homework. I'm learning R and the CFA (configural frequency analysis). I am trying to understand this part of the code so that I can modify it and run a simulation for power analysis of CFA. Thanks again. -- View this message in context: http://r.789695.n4.nabble.com/a-quick-question-about-rbinom-tp4262977p4263919.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list 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.
Re: [R] a quick question about "rbinom"
On Jan 4, 2012, at 7:43 PM, Robert Baer wrote:
-Original Message- From: lynn.tsai
Sent: Wednesday, January 04, 2012 3:38 PM
To: r-help@r-project.org
Subject: [R] a quick question about "rbinom"
Hello, I have the following code using rbinom, but I don't
understand what
*"+1"* means in the code. Could someone help? Thanks so much,
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
It mean index the vector as 1's and 2's (1st and 2nd item in list)
rather than 0's and 1's because R indices start at 1, not 0.
--
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicine
A. T. Still University of Health Sciences
800 W. Jefferson St.
Kirksville, MO 63501
660-626-2322
FAX 660-626-2965
__
R-help@r-project.org mailing list
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.
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
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.
Re: [R] a quick question about "rbinom"
-Original Message-
From: lynn.tsai
Sent: Wednesday, January 04, 2012 3:38 PM
To: r-help@r-project.org
Subject: [R] a quick question about "rbinom"
Hello, I have the following code using rbinom, but I don't understand what
*"+1"* means in the code. Could someone help? Thanks so much,
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
It mean index the vector as 1's and 2's (1st and 2nd item in list) rather
than 0's and 1's because R indices start at 1, not 0.
--
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicine
A. T. Still University of Health Sciences
800 W. Jefferson St.
Kirksville, MO 63501
660-626-2322
FAX 660-626-2965
__
R-help@r-project.org mailing list
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.
Re: [R] a quick question about "rbinom"
On Jan 4, 2012, at 5:31 PM, Justin Haynes wrote:
homework or not,
?rbinom
should be plenty.
I didn't think so. I thought that the answer was:
?"["
--
David.
On Wed, Jan 4, 2012 at 1:38 PM, lynn.tsai
wrote:
Hello, I have the following code using rbinom, but I don't
understand what
*"+1"* means in the code. Could someone help? Thanks so much,
X1<-c("A","B")[rbinom(n,1,0.6)+1]
X2<-c("C","D")[rbinom(n,1,0.1)+1]
--
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
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.
Re: [R] a quick question about "rbinom"
A direct answer to your question:
On Wed, Jan 4, 2012 at 4:38 PM, lynn.tsai wrote:
> Hello, I have the following code using rbinom, but I don't understand what
> *"+1"* means in the code. Could someone help? Thanks so much,
>
>> X1<-c("A","B")[rbinom(n,1,0.6)+1]
>> X2<-c("C","D")[rbinom(n,1,0.1)+1]
Is that the "+1" is adding 1 to the result returned from rbinom().
Look at what happens when you do:
R> c(1, 3, 5, 10) + 1
¡Tada!
If you're just learning R, you'll find it useful to deconstruct
"complex" commands into their "unit" pieces, if you catch my meaning
... look at what rbinom() returns, look at what it returns when you
"+1" it, then look at what you get when you use that whole expression
inside the "[]" to select elements in `c("A", "B")`
You will see the light ...
HTH,
-steve
--
Steve Lianoglou
Graduate Student: Computational Systems Biology
| Memorial Sloan-Kettering Cancer Center
| Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact
__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] a quick question about "rbinom"
homework or not,
?rbinom
should be plenty.
On Wed, Jan 4, 2012 at 1:38 PM, lynn.tsai wrote:
> Hello, I have the following code using rbinom, but I don't understand what
> *"+1"* means in the code. Could someone help? Thanks so much,
>
> > X1<-c("A","B")[rbinom(n,1,0.6)+1]
> > X2<-c("C","D")[rbinom(n,1,0.1)+1]
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/a-quick-question-about-rbinom-tp4262977p4262977.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@r-project.org mailing list
> 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.
>
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] a quick question about "rbinom"
Homework?
If not, context?
-- Bert
On Wed, Jan 4, 2012 at 1:38 PM, lynn.tsai wrote:
> Hello, I have the following code using rbinom, but I don't understand what
> *"+1"* means in the code. Could someone help? Thanks so much,
>
>> X1<-c("A","B")[rbinom(n,1,0.6)+1]
>> X2<-c("C","D")[rbinom(n,1,0.1)+1]
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/a-quick-question-about-rbinom-tp4262977p4262977.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@r-project.org mailing list
> 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.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
__
R-help@r-project.org mailing list
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.
[R] a quick question about "rbinom"
Hello, I have the following code using rbinom, but I don't understand what
*"+1"* means in the code. Could someone help? Thanks so much,
> X1<-c("A","B")[rbinom(n,1,0.6)+1]
> X2<-c("C","D")[rbinom(n,1,0.1)+1]
--
View this message in context:
http://r.789695.n4.nabble.com/a-quick-question-about-rbinom-tp4262977p4262977.html
Sent from the R help mailing list archive at Nabble.com.
__
R-help@r-project.org mailing list
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.
