On Aug 29, 2012, at 7:37 AM, andyspeak wrote:
Hello
I have a huge data frame with three columns 'Roof' 'Month' and 'Temp'
i want to run analyses on the numerical Temp data by the factors
Roof and
Month, separately and together.
For using more than one factor i understand i should use aggregate,
but i am
struggling with the tapply for single factor analysis.
tapply(Temp, INDEX = Roof, FUN = median)
This works fine, however if i try to do anything a bit more complex,
such
as:
tapply(Temp, INDEX = Roof, FUN = kruskal.test)
it gives the error - Error in length(g) : 'g' is missing
What is the sound of one hand clapping?
You are sending a bunch of single vectors with no grouping variable to
a function that is expecting two data columns. Maybe you should
explain what test you had in mind using natural language and we could
help get you there.
--
David Winsemius, MD
Alameda, CA, USA
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