[R] binomial distribution
Hello! I need some help. How I know it to draw the formula of the binomial distribution? expr-expression(P(xi == k) == choose(n, k)* p^k*(1-p)^(n-k)) --- not good on the screen the choose(n, k) not the Binomial Formula, but choose(n, k) Thanx! [[alternative HTML version deleted]] __ 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] binomial distribution
try: ?pbinom -- View this message in context: http://r.789695.n4.nabble.com/binomial-distribution-tp2398568p2398705.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] binomial distribution
On 08/28/2010 10:23 PM, tamas barjak wrote: Hello! I need some help. How I know it to draw the formula of the binomial distribution? expr-expression(P(xi == k) == choose(n, k)* p^k*(1-p)^(n-k)) --- not good on the screen the choose(n, k) not the Binomial Formula, but choose(n, k) Check demo(plotmath), 4th-to-last example. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Phone: (+45)38153501 Email: pd@cbs.dk Priv: pda...@gmail.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] binomial distribution
Perfect! Thank You! 2010/8/28 Peter Dalgaard pda...@gmail.com On 08/28/2010 10:23 PM, tamas barjak wrote: Hello! I need some help. How I know it to draw the formula of the binomial distribution? expr-expression(P(xi == k) == choose(n, k)* p^k*(1-p)^(n-k)) --- not good on the screen the choose(n, k) not the Binomial Formula, but choose(n, k) Check demo(plotmath), 4th-to-last example. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Phone: (+45)38153501 Email: pd@cbs.dk Priv: pda...@gmail.com [[alternative HTML version deleted]] __ 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] binomial distribution
Hi, xiechao
i don't think that is a R specific problem. you mean u got two
random variables X,Y and both
of them binomial distributed and you want to find the distribution of
a new variable Z = X/Y.
That is a basic transformation problem. u can start with introducing a
new r.v. namely W, by
letting it equal to X you obtain W=X,Z=X/Y from which u have X = W
and Y = W / Z. It is easy
to find the Jacobian of this transformation, and the left is routinely.
regards.
On 2008-6-27, at 下午8:29, Xie Chao wrote:
Hi all,
I am a biological student and need your help in statistics.
I have two sets of binomial distributed numbers: {a1, a2, ..., an}
and {b1,
b2, ..., bn}.
How can I get the distribution of the ratios of the two sets of
numbers
{a1/b1, a2/b2, ..., an/bn}? Is there a formula to transform the
distributions? Or where I can start if I want to learn necessary
techniques?
Thank you a lot!
xiechao
[[alternative HTML version deleted]]
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---
Peng Jiang
江鹏
Ph.D. Candidate
Antai College of Economics Management
安泰经济管理学院
Department of Mathematics
数学系
Shanghai Jiaotong University (Minhang Campus)
800 Dongchuan Road
200240 Shanghai
P. R. China
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Re: [R] binomial distribution
Peng Jiang wrote:
Hi, xiechao
i don't think that is a R specific problem. you mean u got two random
variables X,Y and both
of them binomial distributed and you want to find the distribution of
a new variable Z = X/Y.
That is a basic transformation problem. u can start with introducing a
new r.v. namely W, by
letting it equal to X you obtain W=X,Z=X/Y from which u have X = W
and Y = W / Z. It is easy
to find the Jacobian of this transformation, and the left is routinely.
Not that easy! X and Y are discrete, and the result is an improper
distribution since there is a positive probability of dividing by 0. If
the mean of X and Y are moderately large, the delta method can be used.
If they have a small(-ish) number of different values, I'd be tempted
just to use brute force, as in
r - outer(x,y,/)
r[0,0] - 0 # 0/0 defaults to NaN
p - outer(dbinom(x,10,.5), dbinom(y,10,.5))
o - order(r)
plot(r[o],cumsum(p[o]), type=s)
plot(unique(r[o]),tapply(p[o],list(r[o]), sum), type=h)
(the latter plot is not quite right --- should take better care of
rounding issues)
regards.
On 2008-6-27, at 下午8:29, Xie Chao wrote:
Hi all,
I am a biological student and need your help in statistics.
I have two sets of binomial distributed numbers: {a1, a2, ..., an}
and {b1,
b2, ..., bn}.
How can I get the distribution of the ratios of the two sets of numbers
{a1/b1, a2/b2, ..., an/bn}? Is there a formula to transform the
distributions? Or where I can start if I want to learn necessary
techniques?
Thank you a lot!
xiechao
[[alternative HTML version deleted]]
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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.
---
Peng Jiang
江鹏
Ph.D. Candidate
Antai College of Economics Management
安泰经济管理学院
Department of Mathematics
数学系
Shanghai Jiaotong University (Minhang Campus)
800 Dongchuan Road
200240 Shanghai
P. R. China
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R-help@r-project.org mailing list
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PLEASE do read the posting guide
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and provide commented, minimal, self-contained, reproducible code.
--
O__ Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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