extract.mdd.mantelhaen {MDD} | R Documentation |
Takes a response array generated by mdd.mantelhaen.pow
and extracts the minimum detectable difference for the given number of
observed control responses.
extract.mdd.mantelhaen(placebo.vals, from.file = NULL, print.summary = TRUE, sig.inds)
placebo.vals |
number of observed responses in each control stratum. |
from.file |
path for file containing response array created by
mdd.mantelhaen.pow . |
print.summary |
a logical indicating whether to print a summary of the results in paragraph form. |
sig.inds |
only used if from.file is not defined; otherwise, this takes its value from
the object loaded by from.file . |
A list with the following components:
le |
A matrix with rows consisting of all non-comparable (see below) treatment response scenarios for which the test statistic will be significant by virtue of the treatment response rate being less than the control response rate. |
ge |
A matrix with rows consisting of all non-comparable (see below) treatment response scenarios for which the test statistic will be significant by virtue of the treatment response rate being greater than the control response rate. |
If print.summary = TRUE
, this is returned invisibly.
See the Warning section of mdd.mantelhaen.pow
for a note about slight inaccuracies
in the algorithm used there.
“Non-comparable” refers to the fact that if, for example, c(2,3)
is in the le
component, then c(2,2)
, c(1,3)
, c(1,2)
, etc., would all be significant as well.
On the other hand, c(3,2)
and c(0,4)
might or might not be. In particular, for any
two rows in the le
component, there will be at least one column which is strictly greater
in the first row than the second, and at least one column which is strictly greater
in the second row than the first; and similarly for the gr
component.
The function is meant to be used with from.file
rather than sig.inds
, but the
other option is provided for convenience.
Don Barkauskas (barkda@wald.ucdavis.edu)
mdd.mantelhaen.pow
for the form that sig.inds
needs to be in,
mdd.mantelhaen
for a faster version
tmp.file <- paste(tempfile(),".RData",sep="") mh.pow <- mdd.mantelhaen.pow(c(8,9), c(10,7), .25, to.file=tmp.file) mh.pow1 <- extract.mdd.mantelhaen(c(5,4), from.file=tmp.file, print.summary=FALSE) mh.pow2 <- mdd.mantelhaen(c(8,9), c(10,7), c(5,4), print.summary=FALSE) all.equal(mh.pow1, mh.pow2) #Note: they are not identical, because the entries of mh.pow2$gr are of class #"integer", while the entries of mh.pow1$gr are of class "numeric". This #"feature" will be eliminated in a future version of the package (once I figure #out why it's happening). file.remove(tmp.file) rm(tmp.file,mh.pow,mh.pow1,mh.pow2)