birthwt.grpreg {grpreg}R Documentation

Risk Factors Associated with Low Infant Birth Weight

Description

The birthwt.grpreg data frame has 189 rows and 18 columns. The data were collected at Baystate Medical Center, Springfield, Mass during 1986. This data frame is a reparameterization of the birthwt data frame from the MASS package.

Usage

data(birthwt.grpreg)

Format

This data frame contains the following columns:

low
indicator of birth weight less than 2.5kg
bwt
birth weight in kilograms
age1,age2,age3
Orthogonal polynomials of first, second, and third degree representing mother's age in years
lwt1,lwt2,lwt3
Orthogonal polynomials of first, second, and third degree representing mother's weight in pounds at last menstrual period
white,black
Indicator functions for mother's race; "other" is reference group
smoke
smoking status during pregnancy
ptl1,ptl2m
Indicator functions for one or for two or more previous premature labors, respectively. No previous premature labors is the reference category.
ht
history of hypertension
ui
presence of uterine irritability
ftv1,ftv2,ftv3m
Indicator functions for one, for two, or for three or more physician visits during the first trimester, respectively. No visits is the reference category.

Source

MASS. R package. Available at http://cran.r-project.org.

References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
Hosmer, D.W. and Lemeshow, S. (1989) Applied Logistic Regression. New York: Wiley


[Package grpreg version 1.0 Index]