birthwt {MASS} | R Documentation

## Risk Factors Associated with Low Infant Birth Weight

### Description

The `birthwt` data frame has 189 rows and 10 columns. The data were collected at Baystate Medical Center, Springfield, Mass during 1986.

### Usage

    birthwt

### Format

This data frame contains the following columns:

`low`

  indicator of birth weight less than 2.5 kg.

`age`

  mother's age in years.

`lwt`

  mother's weight in pounds at last menstrual period.

`race`

  mother's race (`1` = white, `2` = black, `3` = other).

`smoke`

  smoking status during pregnancy.

`ptl`

  number of previous premature labours.

`ht`

  history of hypertension.

`ui`

  presence of uterine irritability.

`ftv`

  number of physician visits during the first trimester.

`bwt`

  birth weight in grams.

### Source

Hosmer, D.W. and Lemeshow, S. (1989) Applied Logistic Regression. New York: Wiley

### References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### Examples

    attach(birthwt)
    race <- factor(race, labels = c("white", "black", "other"))
    ptd <- factor(ptl > 0)
    ftv <- factor(ftv)
    levels(ftv)[-(1:2)] <- "2+"
    bwt <- data.frame(low = factor(low), age, lwt, race,
        smoke = (smoke > 0), ptd, ht = (ht > 0), ui = (ui > 0), ftv)
    detach("birthwt")
    options(contrasts = c("contr.treatment", "contr.poly"))
    glm(low ~ ., binomial, bwt)

[Package MASS version 7.3-18 Index]