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.

Arguments

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

Format

This data frame contains the following columns:

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)

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