Hi,
Does your data have missing values? I am not sure it would change
anything, but perhaps try adding:
cor(test2, method = "spearman", use = "pairwise.complete.obs")
or something of the like. I am not sure what R does by default. My
reasoning stems from this particular passage in the documentation:
If ‘use’ is ‘"everything"’, ‘NA’s will propagate conceptually,
i.e., a resulting value will be ‘NA’ whenever one of its
contributing observations is ‘NA’.
I do not think the names should make a difference (unless you're
talking about human error).
Best regards,
Josh
On Wed, Sep 8, 2010 at 12:35 PM, Stephane Vaucher
<vauch...@iro.umontreal.ca> wrote:
> Hi everyone,
>
> I'm observing what I believe is weird behaviour when attempting to do
> something very simple. I want a correlation matrix, but my matrix seems to
> contain correlation values that are not found when executed on pairs:
>
>> test2$P2
>
> [1] 2 2 4 4 1 3 2 4 3 3 2 3 4 1 2 2 4 3 4 1 2 3 2 1 3
>>
>> test2$HP_tot
>
> [1] 10 10 10 10 10 10 10 10 136 136 136 136 136 136 136 136 136 136
> 15
> [20] 15 15 15 15 15 15 c=cor(test2$P3,test2$HP_tot,method='spearman')
>>
>> c
>
> [1] -0.2182876
>>
>> c=cor(test2,method='spearman')
>
> Warning message:
> In cor(test2, method = "spearman") : the standard deviation is zero
>>
>> write(c,file='out.csv')
>
> from my spreadsheet
> -0.25028783918741
>
> Most cells are correct, but not that one.
>
> If this is expected behaviour, I apologise for bothering you, I read the
> documentation, but I do not know if the calculation of matrices and pairs is
> done using the same function (eg, with respect to equal value observations).
>
> If this is not a desired behaviour, I noticed that it only occurs with a
> relatively large matrix (I couldn't reproduce on a simple 2 column data
> set). There might be a naming error.
>
>> names(test2)
>
> [1] "ID" "NOMBRE" "MAIL"
> [4] "Age" "SEXO" "Studies"
> [7] "Hours_Internet" "Vision.Disabilities" "Other.disabilities"
> [10] "Technology_Knowledge" "Start_Time" "End_Time"
> [13] "Duration" "P1" "P1Book"
> [16] "P1DVD" "P2" "P3"
> [19] "P4" "P5" "P6"
> [22] "P8" "P9" "P10"
> [25] "P11" "P12" "P7"
> [28] "SITE" "Errors" "warnings"
> [31] "Manual" "Total" "H_tot"
> [34] "HP1.1" "HP1.2" "HP1.3"
> [37] "HP1.4" "HP_tot" "HO1.1"
> [40] "HO1.2" "HO1.3" "HO1.4"
> [43] "HO_tot" "HU1.1" "HU1.2"
> [46] "HU1.3" "HU_tot" "HR"
> [49] "L_tot" "LP1.1" "LP1.2"
> [52] "LP1.3" "LP1.4" "LP_tot"
> [55] "LO1.1" "LO1.2" "LO1.3"
> [58] "LO1.4" "LO_tot" "LU1.1"
> [61] "LU1.2" "LU1.3" "LU_tot"
> [64] "LR_tot" "SP_tot" "SP1.1"
> [67] "SP1.2" "SP1.3" "SP1.4"
> [70] "SP_tot.1" "SO1.1" "SO1.2"
> [73] "SO1.3" "SO1.4" "SO_tot"
> [76] "SU1.1" "SU1.2" "SU1.3"
> [79] "SU_tot" "SR"
>
> Thank you in advance,
> Stephane Vaucher
>
> ______________________________________________
> R-help@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.
>
--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/
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