[R] likelihood from test result

David Bickel dbickel at uottawa.ca
Wed Jan 9 16:46:29 CET 2008


Is there any automatic mechanism for extracting a likelihood or test
statistic distribution (PDF or CDF) from an object of class "htest" or
from another object of a general class encoding a hypothesis test
result?

I would like to have a function that takes "x", an object of class
"htest", as its only argument and that returns the likelihood or test
statistic distribution that was used to compute the p-value. It seems
the only way to write such a function is to manually assign each test
its statistic's distribution, e.g., like this:

FUN <- if(names(x$statistic) == "t")
  dt
else if(names(x$statistic) == "X-squared")
  dchisq
# etc.

Is there a general S3 or S4 class other than "htest" that would better
accommodate such extraction of distributions or likelihoods? I would
also appreciate any suggestions for strategies or contributed packages
that may facilitate automation. For example, would the "distrTEst"
package help?

David

______________________________
David R. Bickel
Ottawa Institute of Systems Biology
http://www.oisb.ca/members.htm




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