[R] e1071::skewness and psych::skew return NaN

[Rui Barradas]

Hello,

That value means that some values of your data are negative or zero. A 
simple inspection shows that

any(dat < 0)  # FALSE
any(dat == 0) # TRUE

Solution: don't log your data


Hope this helps,

Rui Barradas

Em 13-02-2013 16:55, Stephen Politzer-Ahles escreveu:
> Hello everyone,
>
> Does anyone know what would cause the skewness() function (from
> e1071), as well as skew() from psych, to return a value of NaN?
>
> I have a vector of positively-skewed data
> (https://docs.google.com/file/d/0B6-m45Jvl3ZmYzlHRVRHRURzbVk/edit?usp=sharing)
> which these functions return a value for like normal:
>
>> skewness( data ) # returns 1.400405
>
> but when I instead give those functions the log-transformed data they return NaN
>
>> skewness( log( data ) ) #returns NaN
>
> The same occurs when I feed the function data transformed by reflected
> reciprocal
>
>> skewness( max(data) - 1/data ) ) #returns NaN
>
> The vector has no missing values (and if it did, I would get NA rather
> than NaN, and the function wouldn't return a number when I give it the
> raw data).
>
> Best,
> Steve
>
> --
> Stephen Politzer-Ahles
> University of Kansas
> Linguistics Department
> http://people.ku.edu/~sjpa/
>
> ______________________________________________
> R-help at 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.
>