dmft {flexmix} | R Documentation

## Dental data

### Description

Count data from a dental epidemiological study for evaluation of various programs for reducing caries collected among school children from an urban area of Belo Horizonte (Brazil).

### Usage

    data("dmft")

### Format

A data frame with 797 observations on the following 5 variables.

End
  Number of decayed, missing or filled teeth at the end of the study.
Begin
  Number of decayed, missing or filled teeth at the beginning of the study.
Gender
  A factor with levels `male` and `female`.
Ethnic
  A factor with levels `brown`, `white` and `black`.
Treatment
  A factor with levels `control`, `educ`, `enrich`, `rinse`, `hygiene` and `all`.

### Details

The aim of the caries prevention study was to compare four methods to prevent dental caries. Interventions were carried out according to the following scheme:

control
  Control group
educ
  Oral health education
enrich
  Enrichment of the school diet with rice bran
rinse
  Mouthwash with 0.2% sodium floride (NaF) solution
hygiene
  Oral hygiene
all
  All four methods together

### Source

D. Boehning, E. Dietz, P. Schlattmann, L. Mendonca and U. Kirchner (1999): The zero-inflated Poisson model and the decayed, missing and filled teeth index in dental epidemiology. Journal of the Royal Statistical Society A 162(2), pages 195-209.

### Examples

    data("dmft")
    dmft.flx <- stepFlexmix(End ~ 1, data = dmft, k = 2,
                            model = FLXMRglmfix(family = "poisson",
                            fixed = ~ Gender + Ethnic + Treatment))

[Package flexmix version 2.2-4 Index]