Creating two groups of random numbers

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Creating two groups of random numbers

Naike Wang
Hi all,
I want to create two groups of random numbers to calculate proportions. The
first group is to represent the number of cases in a study. The second
group is to represent the sample size of the study. Apparently, the sample
size is going to have to be bigger or equal to the number of cases, but the
sample size of a study is not necessarily greater than the number of cases
of another study. Here's an example:

study                 cases            total
1                        17                 28
2                        48                 70
3                        87                 92
4                        15                 17



Notice that the sample size of the first study is 28, which is bigger than
the number of cases of this study, but is smaller than the number of cases
of the second study.

How do I create a data set like this?

Best,
Naike

        [[alternative HTML version deleted]]

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Re: Creating two groups of random numbers

Boris Steipe
I'd do it this way ... let me know if you need explanations.

minSize <- 15
maxSize <- 100
minSample <- 0.1
maxSample <- 0.8

# setup dataframe with totals, and cases as fractions
myStudies <- data.frame(study = 1:Nstudies,
                        cases = runif(Nstudies,
                                      min = minSample,
                                      max = maxSample),
                        total = sample(minSize:maxSize,
                                       Nstudies,
                                       replace = TRUE))

# convert case fractions of totals to integers
myStudies$cases <- round(myStudies$cases * myStudies$total)


Cheers,
Boris



> On Jun 29, 2017, at 9:44 AM, Naike Wang <[hidden email]> wrote:
>
> Hi all,
> I want to create two groups of random numbers to calculate proportions. The
> first group is to represent the number of cases in a study. The second
> group is to represent the sample size of the study. Apparently, the sample
> size is going to have to be bigger or equal to the number of cases, but the
> sample size of a study is not necessarily greater than the number of cases
> of another study. Here's an example:
>
> study                 cases            total
> 1                        17                 28
> 2                        48                 70
> 3                        87                 92
> 4                        15                 17
>
>
>
> Notice that the sample size of the first study is 28, which is bigger than
> the number of cases of this study, but is smaller than the number of cases
> of the second study.
>
> How do I create a data set like this?
>
> Best,
> Naike
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list -- To UNSUBSCRIBE and more, see
> 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.

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
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and provide commented, minimal, self-contained, reproducible code.
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Re: Creating two groups of random numbers

Michael Dewey-3
In reply to this post by Naike Wang
Please do not cross post as people waste time replying on one forum not
knowing you have already received excellent advice on another.

On 29/06/2017 14:44, Naike Wang wrote:

> Hi all,
> I want to create two groups of random numbers to calculate proportions. The
> first group is to represent the number of cases in a study. The second
> group is to represent the sample size of the study. Apparently, the sample
> size is going to have to be bigger or equal to the number of cases, but the
> sample size of a study is not necessarily greater than the number of cases
> of another study. Here's an example:
>
> study                 cases            total
> 1                        17                 28
> 2                        48                 70
> 3                        87                 92
> 4                        15                 17
>
>
>
> Notice that the sample size of the first study is 28, which is bigger than
> the number of cases of this study, but is smaller than the number of cases
> of the second study.
>
> How do I create a data set like this?
>
> Best,
> Naike
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
> ---
> This email has been checked for viruses by AVG.
> http://www.avg.com
>
>

--
Michael
http://www.dewey.myzen.co.uk/home.html

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
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.