svyquantile

0th

Percentile

Summary statistics for sample surveys

Compute means, variances, quantiles, and cross-tabulations for data from complex surveys.

Keywords
univar, survey
Usage
svyquantile(x, design, quantiles, method = "linear", f = 1)
svymean(x, design, na.rm=FALSE) 
svrepmean(x, design, na.rm=FALSE, rho=NULL, return.replicates=FALSE) 
svyvar(x, design, na.rm=FALSE) 
svytotal(x, design, na.rm=FALSE) 
svreptotal(x, design, na.rm=FALSE, rho=NULL, return.replicates=FALSE) 
svytable(formula, design, Ntotal = design$fpc, round = FALSE)
svreptable(formula, design, Ntotal = sum(weights(design, "sampling"))), round = FALSE)
Arguments
x
A formula, vector or matrix
design
survey.design object
quantiles
Quantiles to estimate
method
see approxfun
f
see approxfun
na.rm
Should missing values be removed?
formula
A one-sided formula specifying variables to be tabulated
Ntotal
A population total or set of population stratum totals to normalise to.
round
Should the table entries be rounded to the nearest integer?
rho
parameter for Fay's variance estimator in a BRR design
return.replicates
Return the replicate means?
Details

These functions perform weighted estimation, with each observation being weighted by the inverse of its sampling probability. The svymean and svyvar functions also give precision estimates that incorporate the effects of stratification and clustering. The first four functions are similar to the standard functions whose names do not begin with svy.

The svytotal and svreptotal functions estimate a population total. Use predict on svyratio, svrepratio, svyglm, svrepglm to get ratio or regression estimates of totals.

The svytable and svreptable function computes a weighted crosstabulation. If the sampling probabilities supplied to svydesign were actual probabilities (rather than relative probabilities) this estimates a full population crosstabulation. Otherwise it estimates only relative proportions and should be normalised to some convenient total such as 100 or 1.0 by specifying the Ntotal argument.

The Ntotal argument can be either a single number or a data frame whose first column is the sampling strata and second column the population size in each stratum. In this second case the svytable command performs `post-stratification': tabulating and scaling to the population within strata and then adding up the strata.

As with other xtabs objects, the output of svytable can be processed by ftable for more attractive display.

Value

  • The first three functions return vectors, the last returns an xtabs object.

See Also

svydesign, svyCprod, mean,var, quantile, xtabs

Aliases
  • svyquantile
  • svytable
  • svreptable
  • svymean
  • svrepmean
  • svytotal
  • svreptotal
  • svyvar
Examples
#population
  df<-data.frame(x=rnorm(1000),z=rep(0:4,200))
  df$y<-with(df, 3+3*x*z)
  #sampling fraction
  df$p<-with(df, exp(x)/(1+exp(x)))
  #sample
  xi<-rbinom(1000,1,df$p)
  sdf<-df[xi==1,]
  
  #survey design object: independent sampling, 
  dxi<-svydesign(~0,~p,data=sdf)
  dxi

  mean(df$x)		#right
  mean(sdf$x)		#wrong
  svymean(~x,dxi)	#right

  var(df$x)		#right
  var(sdf$x)		#wrong
  svyvar(~x,dxi)	#right

  quantile(df$x,c(0.025,0.5,0.975))  #right
  quantile(sdf$x,c(0.025,0.5,0.975))  #wrong
  svyquantile(~x,design=dxi,c(0.025,0.5,0.975))  #right

  table(sdf$z)  # sample table
  svytable(~z, dxi, round=TRUE) # estimated population table

  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)
  svrepmean(~arrests+alive, design=scdrep)
Documentation reproduced from package survey, version 1.9-2, License: LGPL

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