Add variables to replicated objects

Modifies a kott.design object by adding new variables to it.

kott.addvars(deskott, ...)

Arguments

deskott	Object of class kott.design containing the replicated survey data.
…	tag = expr arguments defining columns to be added to deskott.

Details

This function adds to the data frame contained in deskott the new variables defined by the tag = expr arguments. A tag can be specified either by means of an identifier or by a character string; expr can be any expression that it makes sense to evaluate in the deskott environment.

For each argument tag = expr bound to the formal argument … the added column will have name given by the tag value and values obtained by evaluating the expr expression on deskott. Any input expression unsupplied with a tag will be ignored and will therefore have no effect on the kott.addvars return value.

Variables to be added to the input replicated object have to be new: namely it is not possible to use kott.addvars to modify the values in a pre-existing deskott column.

Value

An object of the same class of deskott, containing new variables but supplied with exactly the same metadata.

Examples

data(data.examples)

# Creation of a kott.design object:
kdes<-kottdesign(data=example,ids=~towcod+famcod,strata=~SUPERSTRATUM,
      weights=~weight,nrg=15)

# Adding the new 'population' variable to estimate the number
# of final units in the population: 
kdes2<-kott.addvars(kdes,population=1)
kottby(kdes2,~population)
#>               total      SE
#> population 924101.3 22059.9

# Recoding a qualitative variable:
kdes2<-kott.addvars(kdes,agerange=as.factor(ifelse(age5c==1,
                                            "young","not-young")))
kottby(kdes2,~agerange,est="mean")
#>                         mean          SE
#> agerange.not-young 0.8604824 0.007587145
#> agerange.young     0.1395176 0.007587145
kottby(kdes2,~income,~agerange,estimator="mean",conf.int=TRUE)
#>             not-young    young
#> mean         1303.762 962.6162
#> SE           10.45407 20.86844
#> l.conf(95%)   1281.34 917.8579
#> u.conf(95%)  1326.184 1007.375

# Algebraic operations on numeric variables:
kdes2<-kott.addvars(kdes,q=income/z^2)
kottby(kdes2,~q)
#>      total       SE
#> q 101910.2 3071.595