Correlation Matrix - p value?

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Correlation Matrix - p value?

ScottM
Hello all,

I've run a Spearman's Rank test to discern relationships between landscape characteristics and a specific aspect of river behaviour.

I've executed a correlation matrix between the one dependent variable and all of the predictors, which gives me a nice output of Spearman's Rho values.

However, I also need to somehow find the "p" value, to assess the strength of relationship.  

Conducting a simple correlation between 2 variables using the:

cor(var1, var2, method="spearman")

command gives me an output with both the Rho and P value, but the default output of the matrix is simply the Rho value.  I've tried using summary(result), but it just produces the percentile/max/min values.

Any help appreciated.

Cheers,

S.
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Re: Correlation Matrix - p value?

Jorge I Velez
?cor.test
cor.test(x, y, method = "spearman")$p.value

HTH,
Jorge


On Tue, Aug 9, 2011 at 8:44 AM, ScottM <> wrote:

> Hello all,
>
> I've run a Spearman's Rank test to discern relationships between landscape
> characteristics and a specific aspect of river behaviour.
>
> I've executed a correlation matrix between the one dependent variable and
> all of the predictors, which gives me a nice output of Spearman's Rho
> values.
>
> However, I also need to somehow find the "p" value, to assess the strength
> of relationship.
>
> Conducting a simple correlation between 2 variables using the:
>
> cor(var1, var2, method="spearman")
>
> command gives me an output with both the Rho and P value, but the default
> output of the matrix is simply the Rho value.  I've tried using
> summary(result), but it just produces the percentile/max/min values.
>
> Any help appreciated.
>
> Cheers,
>
> S.
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729838.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] 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.
>

        [[alternative HTML version deleted]]

______________________________________________
[hidden email] 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.
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RE: Correlation Matrix - p value?

ScottM
Cheers Jorge,

I've tried this, but keep getting error messages, relating to either:

Error: unexpected '$' in "$"

or

Error in cor(data, method = "spearman")$p.value :
  $ operator is invalid for atomic vectors

Very annoying!

S

Scott McGrane MA (Hons), MRes
SAGES Theme 1 PhD Student
Northern Rivers Institute
St Mary's Building
University of Aberdeen

http://www.abdn.ac.uk/nri
________________________________________
From: Jorge Ivan Velez [via R] [[hidden email]]
Sent: 09 August 2011 01:55 PM
To: Mcgrane, Scott
Subject: Re: Correlation Matrix - p value?

?cor.test
cor.test(x, y, method = "spearman")$p.value

HTH,
Jorge


On Tue, Aug 9, 2011 at 8:44 AM, ScottM <> wrote:

> Hello all,
>
> I've run a Spearman's Rank test to discern relationships between landscape
> characteristics and a specific aspect of river behaviour.
>
> I've executed a correlation matrix between the one dependent variable and
> all of the predictors, which gives me a nice output of Spearman's Rho
> values.
>
> However, I also need to somehow find the "p" value, to assess the strength
> of relationship.
>
> Conducting a simple correlation between 2 variables using the:
>
> cor(var1, var2, method="spearman")
>
> command gives me an output with both the Rho and P value, but the default
> output of the matrix is simply the Rho value.  I've tried using
> summary(result), but it just produces the percentile/max/min values.
>
> Any help appreciated.
>
> Cheers,
>
> S.
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729838.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=0> 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.
>

        [[alternative HTML version deleted]]

______________________________________________
[hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=1> 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.


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Re: Correlation Matrix - p value?

Michael Weylandt
Just pointing out that Jorge wrote

cor.test

not cor.

Don't know if you saw that but it should help.

Michael Weylandt


On Aug 9, 2011, at 8:58 AM, ScottM <[hidden email]> wrote:

> Cheers Jorge,
>
> I've tried this, but keep getting error messages, relating to either:
>
> Error: unexpected '$' in "$"
>
> or
>
> Error in cor(data, method = "spearman")$p.value :
>  $ operator is invalid for atomic vectors
>
> Very annoying!
>
> S
>
> Scott McGrane MA (Hons), MRes
> SAGES Theme 1 PhD Student
> Northern Rivers Institute
> St Mary's Building
> University of Aberdeen
>
> http://www.abdn.ac.uk/nri
> ________________________________________
> From: Jorge Ivan Velez [via R] [[hidden email]]
> Sent: 09 August 2011 01:55 PM
> To: Mcgrane, Scott
> Subject: Re: Correlation Matrix - p value?
>
> ?cor.test
> cor.test(x, y, method = "spearman")$p.value
>
> HTH,
> Jorge
>
>
> On Tue, Aug 9, 2011 at 8:44 AM, ScottM <> wrote:
>
>> Hello all,
>>
>> I've run a Spearman's Rank test to discern relationships between landscape
>> characteristics and a specific aspect of river behaviour.
>>
>> I've executed a correlation matrix between the one dependent variable and
>> all of the predictors, which gives me a nice output of Spearman's Rho
>> values.
>>
>> However, I also need to somehow find the "p" value, to assess the strength
>> of relationship.
>>
>> Conducting a simple correlation between 2 variables using the:
>>
>> cor(var1, var2, method="spearman")
>>
>> command gives me an output with both the Rho and P value, but the default
>> output of the matrix is simply the Rho value.  I've tried using
>> summary(result), but it just produces the percentile/max/min values.
>>
>> Any help appreciated.
>>
>> Cheers,
>>
>> S.
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729838.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> [hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=0> 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.
>>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=1> 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.
>
>
> ________________________________
> If you reply to this email, your message will be added to the discussion below:
> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729864.html
> To unsubscribe from Correlation Matrix - p value?, click here<
>
>
> The University of Aberdeen is a charity registered in Scotland, No SC013683.
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729868.html
> Sent from the R help mailing list archive at Nabble.com.
>    [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] 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.

______________________________________________
[hidden email] 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.
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Re: Correlation Matrix - p value?

djmuseR
In reply to this post by ScottM
Works for me:

> x <- rnorm(10)
> y <- rnorm(10)
> cor.test(x, y, method = 'spearman')$p.value
[1] 0.166058


What are the classes of your inputs? A reproducible example would be
helpful. From the help page of cor.test():

x, y numeric vectors of data values. x and y must have the same length.

Do your two inputs meet those criteria?

HTH,
Dennis

On Tue, Aug 9, 2011 at 5:58 AM, ScottM <[hidden email]> wrote:

> Cheers Jorge,
>
> I've tried this, but keep getting error messages, relating to either:
>
> Error: unexpected '$' in "$"
>
> or
>
> Error in cor(data, method = "spearman")$p.value :
>  $ operator is invalid for atomic vectors
>
> Very annoying!
>
> S
>
> Scott McGrane MA (Hons), MRes
> SAGES Theme 1 PhD Student
> Northern Rivers Institute
> St Mary's Building
> University of Aberdeen
>
> http://www.abdn.ac.uk/nri
> ________________________________________
> From: Jorge Ivan Velez [via R] [[hidden email]]
> Sent: 09 August 2011 01:55 PM
> To: Mcgrane, Scott
> Subject: Re: Correlation Matrix - p value?
>
> ?cor.test
> cor.test(x, y, method = "spearman")$p.value
>
> HTH,
> Jorge
>
>
> On Tue, Aug 9, 2011 at 8:44 AM, ScottM <> wrote:
>
>> Hello all,
>>
>> I've run a Spearman's Rank test to discern relationships between landscape
>> characteristics and a specific aspect of river behaviour.
>>
>> I've executed a correlation matrix between the one dependent variable and
>> all of the predictors, which gives me a nice output of Spearman's Rho
>> values.
>>
>> However, I also need to somehow find the "p" value, to assess the strength
>> of relationship.
>>
>> Conducting a simple correlation between 2 variables using the:
>>
>> cor(var1, var2, method="spearman")
>>
>> command gives me an output with both the Rho and P value, but the default
>> output of the matrix is simply the Rho value.  I've tried using
>> summary(result), but it just produces the percentile/max/min values.
>>
>> Any help appreciated.
>>
>> Cheers,
>>
>> S.
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729838.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> [hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=0> 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.
>>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email]</user/SendEmail.jtp?type=node&node=3729864&i=1> 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.
>
>
> ________________________________
> If you reply to this email, your message will be added to the discussion below:
> http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729864.html
> To unsubscribe from Correlation Matrix - p value?, click here<
>
>
> The University of Aberdeen is a charity registered in Scotland, No SC013683.
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Correlation-Matrix-p-value-tp3729838p3729868.html
> Sent from the R help mailing list archive at Nabble.com.
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] 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.
>

______________________________________________
[hidden email] 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.