R help - Apr 2016 - [FORGED] Generating random data with non-linear correlation between two variables

Hi All,

I am new to R and don't know how to achieve it.

I am interested in generating a hypothetical dataframe that is consisted of say
two variables named v1 and v2, based on the following constraints:
1. The range of v1 is 500-1500.
2. The mean of v1 is say 1100
3. The range of v2 is 300-950.
4. The mean of v2 is say 400
5. There exists a positive trend between these two variables, meaning that as v1
increases, v2 be also increase.
6. But the trend should be slightly non-linear. i.e., curved line.

Is it possible to automatically generate through functions like rnorm.

Any help will be highly appreciated.

Many Thanks and

Kind Regards

--
Muhammad Bilal
Research Assistant and Doctoral Researcher,
Bristol Enterprise, Research and Innovation Centre (BERIC),
University of the West of England (UWE),
Frenchay Campus,
Bristol,
BS16 1QY

muhammad2.bilal at live.uwe.ac.uk<mailto:olugbenga2.akinade at
live.uwe.ac.uk>


	[[alternative HTML version deleted]]

Hello,


I changed the last 3 lines from v1 and v2 to myData$v1 and myData$v2.

Creating the vectors in not a problem.
Where you will run into issues is when you create the data.frame.
The length of v1 is 1001 and the length of v2 is 651.
The warning message below is telling us that the lengths of v1 and v2 
are different.
"Shorter vectors are recycled as often as need be until they match the 
length of the longest vector."

See section 2.2 of this document for more on recycling.
https://cran.r-project.org/doc/manuals/R-intro.pdf

    v1 <- sort(rnorm(500:1500, mean = 1100, sd = 1), decreasing = F)
    v2 <- sort(rnorm(300:950, mean = 400, sd = 1), decreasing = F)
    length(v1)
    length(v2)
    myData <- data.frame(cbind(v1, v2))

         Warning message:
          In cbind(v1, v2) :
         number of rows of result is not a multiple of vector length (arg 2)

    plot(myData$v1, myData$v2, type = "l")

    cor(myData$v1, myData$v2, method = "pearson")

    plot(myData, type = 'l')

Michael Long


On 04/08/2016 11:57 AM, Muhammad Bilal wrote:
> Hi All,
>
> I am new to R and don't know how to achieve it.
>
> I am interested in generating a hypothetical dataframe that is consisted of
say two variables named v1 and v2, based on the following constraints:
> 1. The range of v1 is 500-1500.
> 2. The mean of v1 is say 1100
> 3. The range of v2 is 300-950.
> 4. The mean of v2 is say 400
> 5. There exists a positive trend between these two variables, meaning that
as v1 increases, v2 be also increase.
> 6. But the trend should be slightly non-linear. i.e., curved line.
>
> Is it possible to automatically generate through functions like rnorm.
>
> Any help will be highly appreciated.
>
> Many Thanks and
>
> Kind Regards
>
> --
> Muhammad Bilal
> Research Assistant and Doctoral Researcher,
> Bristol Enterprise, Research and Innovation Centre (BERIC),
> University of the West of England (UWE),
> Frenchay Campus,
> Bristol,
> BS16 1QY
>
> muhammad2.bilal at live.uwe.ac.uk<mailto:olugbenga2.akinade at
live.uwe.ac.uk>
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org 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.

	[[alternative HTML version deleted]]

On 09/04/16 06:57, Muhammad Bilal wrote:
> Hi All,
>
> I am new to R and don't know how to achieve it.
>
> I am interested in generating a hypothetical dataframe that is consisted of
say two variables named v1 and v2, based on the following constraints:
> 1. The range of v1 is 500-1500.
> 2. The mean of v1 is say 1100
> 3. The range of v2 is 300-950.
> 4. The mean of v2 is say 400
> 5. There exists a positive trend between these two variables, meaning that
as v1 increases, v2 be also increase.
> 6. But the trend should be slightly non-linear. i.e., curved line.
>
> Is it possible to automatically generate through functions like rnorm.
>
> Any help will be highly appreciated.
This sounds to me very much like a homework problem.  We don't do 
people's homework for them on this list.

cheers,

Rolf Turner

-- 
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

Hi Rolf Turner,

Firstly, I really appreciate your help.

Is it possible to give the number of entries I need so that rnorm function
generates only that number of rows?

Also is it possible to generate the points with spread randomly such that they
don't overlap each other too much.

Many Thanks and 

Kind Regards
--
Muhammad Bilal
Research Assistant and PhD Student,
Bristol Enterprise, Research and Innovation Centre (BERIC),
University of the West of England (UWE),
Frenchay Campus,
Bristol,
BS16 1QY

muhammad2.bilal at live.uwe.ac.uk


________________________________________
From: Rolf Turner <r.turner at auckland.ac.nz>
Sent: 09 April 2016 04:46
To: Muhammad Bilal
Cc: r-help at r-project.org
Subject: Re: [FORGED] [R] Generating random data with non-linear correlation
between two variables

On 09/04/16 06:57, Muhammad Bilal wrote:
> Hi All,
>
> I am new to R and don't know how to achieve it.
>
> I am interested in generating a hypothetical dataframe that is consisted of
say two variables named v1 and v2, based on the following constraints:
> 1. The range of v1 is 500-1500.
> 2. The mean of v1 is say 1100
> 3. The range of v2 is 300-950.
> 4. The mean of v2 is say 400
> 5. There exists a positive trend between these two variables, meaning that
as v1 increases, v2 be also increase.
> 6. But the trend should be slightly non-linear. i.e., curved line.
>
> Is it possible to automatically generate through functions like rnorm.
>
> Any help will be highly appreciated.
This sounds to me very much like a homework problem.  We don't do
people's homework for them on this list.

cheers,

Rolf Turner

--
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

No its not. I am doing all these experiments for my own learning purpose. I am
Oracle SQL & PLSQL programmer and  I can do these things with Oracle
analytical functions.

However at present I am keen to learn R, with no other interest right now.

Thanks
--
Muhammad Bilal
Research Assistant and PhD Student,
Bristol Enterprise, Research and Innovation Centre (BERIC),
University of the West of England (UWE),
Frenchay Campus,
Bristol,
BS16 1QY

muhammad2.bilal at live.uwe.ac.uk


________________________________________
From: Rolf Turner <r.turner at auckland.ac.nz>
Sent: 09 April 2016 04:46
To: Muhammad Bilal
Cc: r-help at r-project.org
Subject: Re: [FORGED] [R] Generating random data with non-linear correlation
between two variables

On 09/04/16 06:57, Muhammad Bilal wrote:
> Hi All,
>
> I am new to R and don't know how to achieve it.
>
> I am interested in generating a hypothetical dataframe that is consisted of
say two variables named v1 and v2, based on the following constraints:
> 1. The range of v1 is 500-1500.
> 2. The mean of v1 is say 1100
> 3. The range of v2 is 300-950.
> 4. The mean of v2 is say 400
> 5. There exists a positive trend between these two variables, meaning that
as v1 increases, v2 be also increase.
> 6. But the trend should be slightly non-linear. i.e., curved line.
>
> Is it possible to automatically generate through functions like rnorm.
>
> Any help will be highly appreciated.
This sounds to me very much like a homework problem.  We don't do
people's homework for them on this list.

cheers,

Rolf Turner

--
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276