[R] How to generate fake population (ie. not sample) data?

Gabor Grothendieck ggrothendieck at gmail.com
Wed Mar 4 12:17:09 CET 2009


On Wed, Mar 4, 2009 at 2:48 AM, Daniel Nordlund <djnordlund at verizon.net> wrote:
>> -----Original Message-----
>> From: r-help-bounces at r-project.org
>> [mailto:r-help-bounces at r-project.org] On Behalf Of CB
>> Sent: Tuesday, March 03, 2009 10:05 PM
>> To: David Winsemius
>> Cc: r-help at r-project.org
>> Subject: Re: [R] How to generate fake population (ie. not
>> sample) data?
>>
>> My understanding is that rnorm(n, x, s) will give me an n-sized sample
>> from an (x, s) normal distribution. So the vector returned will have a
>> mean from the sampling distribution of the mean. But what I want is a
>> set of n numbers literally with a mean of x and sd of s.
>>
>> I am at the very beginning of my R journey, so my apologies if this is
>> a particularly naive enquiry.
>>
>> 2009/3/4 David Winsemius <dwinsemius at comcast.net>:
>> > In what ways is rnorm not a satisfactory answer?
>> >
>> > --
>> > David Winsemius
>> >
>> > On Mar 3, 2009, at 9:33 PM, CB wrote:
>> >
>> >> This seems like it should be obvious, but searches I've
>> tried all come
>> >> up with rnorm etc.
>> >>
>> >> Is there a way of generating normally-distributed 'population' data
>> >> with known parameters?
>> >>
>> >> Cheers, CB.
>> >>
>
> Something like this may help get you started.
>
> std.pop <- function(x,mu,stdev){
>  ((x-mean(x))/sd(x)*stdev)+mu
>  }

Note the scale function, i.e. the above can also be written:

stdev * scale(x) + mu


>
> population <- std.pop(rnorm(1000),10,5)
>
> Hope this is helpful,
>
> Dan
>
> Daniel Nordlund
> Bothell, WA USA
>
> ______________________________________________
> 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.
>




More information about the R-help mailing list