Dear all,
I use R 3.1.1 for Windows.
kindly how can I generate n number of random numbers with probability from [0,1]
and their sum must not be more than one
thanks in advance
Ragia
[[alternative HTML version deleted]]
Well, if their sum must be < 1 they ain't random...
But anyway... given n
randnums <- function(n)
{
Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374
"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
Clifford Stoll
On Sat, Nov 22, 2014 at 6:29 AM, Ragia Ibrahim <ragia11 at hotmail.com>
wrote:>
> Dear all,
> I use R 3.1.1 for Windows.
> kindly how can I generate n number of random numbers with probability from
[0,1]
> and their sum must not be more than one
> thanks in advance
> Ragia
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.
(Hit send key by accident before I was finished ...) Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." Clifford Stoll On Sat, Nov 22, 2014 at 7:14 AM, Bert Gunter <bgunter at gene.com> wrote:> Well, if their sum must be < 1 they ain't random... >But anyway, one way is ... given n randnums <- function(n) { u <- runif(n) u/sum(u) } Bert Gunter> > > On Sat, Nov 22, 2014 at 6:29 AM, Ragia Ibrahim <ragia11 at hotmail.com> wrote: >> >> Dear all, >> I use R 3.1.1 for Windows. >> kindly how can I generate n number of random numbers with probability from [0,1] >> and their sum must not be more than one >> thanks in advance >> Ragia >> >> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at 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.
These are contradictory requirements: either you have n random numbers from the interval [0,1), then you can't guarantee anything about their sum except that it will be in [0,n). Or you constrain the sum, then your random numbers cannot be random in [0,1). You could possibly scale the random numbers: n <- 13 x <- runif(n) x <- x / sum(x) x; sum(x) This will guarantee that their sum is 1 (to numerical accuracy), but your numbers are then effectively drawn from the interval [0,2/n) for large n. B. On Nov 22, 2014, at 9:29 AM, Ragia Ibrahim <ragia11 at hotmail.com> wrote:> > Dear all, > I use R 3.1.1 for Windows. > kindly how can I generate n number of random numbers with probability from [0,1] > and their sum must not be more than one > thanks in advance > Ragia > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.
I don't understand this discussion at all. n random numbers constrained to have sum <=1 are still random. They are not all independent. That said, the original poster's question is ill=formed since there can be multiple distributions these random numbers come from. best wishes, Ranjan On Sat, 22 Nov 2014 10:29:18 -0500 Boris Steipe <boris.steipe at utoronto.ca> wrote:> These are contradictory requirements: either you have n random numbers from the interval [0,1), then you can't guarantee anything about their sum except that it will be in [0,n). Or you constrain the sum, then your random numbers cannot be random in [0,1). You could possibly scale the random numbers: > n <- 13 > x <- runif(n) > x <- x / sum(x) > x; sum(x) > > This will guarantee that their sum is 1 (to numerical accuracy), but your numbers are then effectively drawn from the interval [0,2/n) for large n. > > B. > > > On Nov 22, 2014, at 9:29 AM, Ragia Ibrahim <ragia11 at hotmail.com> wrote: > > > > > Dear all, > > I use R 3.1.1 for Windows. > > kindly how can I generate n number of random numbers with probability from [0,1] > > and their sum must not be more than one > > thanks in advance > > Ragia > > > > > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help at 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-help at 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. >-- Important Notice: This mailbox is ignored: e-mails are set to be deleted on receipt. Please respond to the mailing list if appropriate. For those needing to send personal or professional e-mail, please use appropriate addresses. ____________________________________________________________ FREE ONLINE PHOTOSHARING - Share your photos online with your friends and family! Visit http://www.inbox.com/photosharing to find out more!