[R] How to use Subpopulation data?
David Winsemius
dwinsemius at comcast.net
Sat Oct 3 01:53:08 CEST 2009
On Oct 2, 2009, at 2:39 PM, KABELI MEFANE wrote:
> Dear Mr Winsemius
>
> I am sorry to have offended any of you by the mistakes i made. The
> package i loaded is sampling and there was an unwanted comma between
> size c(20, )and the bracket. What i wanted was to calculate the sum
> of H in a sample not in the original dataframe. If i do
> sum(H) i get the sum value of H's in the original dataframe.
Yes, and that would be expected, would it not?
>
>
> Load package sampling
>
> H <- matrix(rnorm(100, mean=50000, sd=5000))
> sampleframe=data.frame(type=c(rep("H",100)),value=c(H))
> sampleframe
> sum(H)
>
> str=strata(sampleframe,c("type"),size=c(20), method="srswor")
> sample.strat<-getdata(sampleframe,str)
> sample.strat
Seems to me that you should be getting descriptive statisics on the
sample.strat object rather than on H.
> summary(sample.strat)
value type ID_unit Prob Stratum
Min. :37931 H:20 Min. : 1.00 Min. :0.2 Min. :1
1st Qu.:46547 1st Qu.:20.75 1st Qu.:0.2 1st Qu.:1
Median :48848 Median :44.50 Median :0.2 Median :1
Mean :49193 Mean :50.45 Mean :0.2 Mean :1
3rd Qu.:51311 3rd Qu.:78.75 3rd Qu.:0.2 3rd Qu.:1
Max. :58523 Max. :98.00 Max. :0.2 Max. :1
>
>
> Thanks for the input. Once again sorry for wasting your time.
>
> Best Regards
>
>
>
>
> --- On Fri, 2/10/09, David Winsemius <dwinsemius at comcast.net> wrote:
>
> From: David Winsemius <dwinsemius at comcast.net>
> Subject: Re: [R] How to use Subpopulation data?
> To: "KABELI MEFANE" <kabelimefane at yahoo.co.uk>
> Cc: R-help at r-project.org
> Date: Friday, 2 October, 2009, 3:38 PM
>
>
> On Oct 1, 2009, at 6:06 AM, KABELI MEFANE wrote:
>
> > Dear Helpers
> >
> > I have a sample frame and i have sampled from it using three
> methods and now i want to calculate the statistics but i only get
> the population parameters.
> >
> > H <- matrix(rnorm(100, mean=50000, sd=5000))
> > sampleframe=data.frame(type=c(rep("H",100)),value=c(H))
> > sampleframe
> >
> > str=strata(sampleframe,c("type"),size=c(20,), method="srswor")
> > sample.strat<-getdata(sampleframe,str)
> > sample.strat
>
> If you want the number of rows in sample.strat then length(H) is the
> wrong approach since that is the original (unsampled) object.
>
> > length(H)
> > i get:
> >
> > length(H)
> > [1] 100
> >
> > Desire to get:
> > length(H)
> > [1] 20
>
> I cannot tell what packages you have loaded and strata is not in the
> sampling package which I guessed (wrongly) was where you were
> getting "getdata". When you post code you should precede that code
> with calls that load any non-base packages.
>
> In later posting you ask for ways to calculate "the sum" but you do
> not say what it is that you want the sum of.... . Our abilities to
> read minds is extremely limited.
>
> --David Winsemius
>
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