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

data(birthwt)

Format

This data frame contains the following columns:

low

indicator of birth weight less than 2.5kg

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

Examples

data(birthwt)
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)