| withReplicates {survey} | R Documentation |
Given a function or expression computing a statistic based on sampling
weights, withReplicates evaluates the statistic and produces a
replicate-based estimate of variance.
withReplicates(design, theta, rho = NULL, ..., scale.weights=FALSE, return.replicates=FALSE)
design |
A survey design with replicate weights (eg from svrepdesign) |
theta |
A function or expression: see Details below |
rho |
If design uses BRR weights, rho optionally
specifies the parameter for Fay's variance estimator. |
... |
Other arguments to theta |
scale.weights |
Divide the probability weights by their sum (can help with overflow problems) |
return.replicates |
Return the replicate estimates as well as the variance? |
If theta is a function its first argument will be a vector of
weights and the second argument will be a data frame containing the
variables from the design object.
If it is an expression, the sampling weights will be available as the
variable .weights. Variables in the design object will also
be in scope. It is possible to use global variables in the
expression, but unwise, as they may be masked by local variables
inside withReplicates.
If return.replicates=FALSE, the weighted statistic, with the
variance matrix as the "var" attribute. If
return.replicates=TRUE, a list with elements theta for
the usual return value and replicates for the replicates.
svrepdesign, as.svrepdesign, svrVar
data(scd) repweights<-2*cbind(c(1,0,1,0,1,0), c(1,0,0,1,0,1), c(0,1,1,0,0,1), c(0,1,0,1,1,0)) scdrep<-svrepdesign(data=scd, type="BRR", repweights=repweights) a<-svyratio(~alive, ~arrests, design=scdrep) print(a$ratio) print(a$var) withReplicates(scdrep, quote(sum(.weights*alive)/sum(.weights*arrests))) withReplicates(scdrep, function(w,data) sum(w*data$alive)/sum(w*data$arrests))