svycontrast {survey} | R Documentation |

## Linear and nonlinearconstrasts of survey statistics

### Description

Computes linear or nonlinear contrasts of estimates produced by survey
functions (or any object with `coef`

and `vcov`

methods).

### Usage

svycontrast(stat, contrasts, ...)

### Arguments

`stat` |
object of class `svrepstat` or `svystat` |

`contrasts` |
A vector or list of vectors of coefficients, or a
call or list of calls |

`...` |
For future expansion |

### Details

If `contrasts`

is a list, the element names are used as
names for the returned statistics.

If an element of `contrasts`

is shorter than `coef(stat)`

and has names, the
names are used to match up the vectors and the remaining elements of
`contrasts`

are assumed to be zero. If the names are not legal
variable names (eg `0.1`

) they must be quoted (eg `"0.1"`

)

If `contrasts`

is a `"call"`

or list of `"call"s`

, the
delta-method is used to compute variances, and the calls must use only
functions that `deriv`

knows how to differentiate. If the
names are not legal variable names they must be quoted with backticks
(eg ``0.1``

).

### Value

Object of class `svrepstat`

or `svystat`

### See Also

`regTermTest`

, `svyglm`

### Examples

data(api)
dclus1<-svydesign(id=~dnum, weights=~pw, data=apiclus1, fpc=~fpc)
a <- svytotal(~api00+enroll+api99, dclus1)
svycontrast(a, list(avg=c(0.5,0,0.5), diff=c(1,0,-1)))
## if contrast vectors have names, zeroes may be omitted
svycontrast(a, list(avg=c(api00=0.5,api99=0.5), diff=c(api00=1,api99=-1)))
## nonlinear contrasts
svycontrast(a, quote(api00/api99))
svyratio(~api00, ~api99, dclus1)

[Package

*survey* version 3.18

Index]