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/
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