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<html><head><title>R: Risk Factors Associated with Low Infant Birth Weight</title>
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<table width="100%" summary="page for birthwt {MASS}"><tr><td>birthwt {MASS}</td><td align="right">R Documentation</td></tr></table>
<h2>Risk Factors Associated with Low Infant Birth Weight</h2>
<h3>Description</h3>
<p>
The <code>birthwt</code> data frame has 189 rows and 10 columns.
The data were collected at Baystate Medical Center, Springfield, Mass
during 1986.
</p>
<h3>Usage</h3>
<pre>
birthwt
</pre>
<h3>Format</h3>
<p>
This data frame contains the following columns:
<dl>
<dt><code>low</code></dt><dd>indicator of birth weight less than 2.5kg
</dd>
<dt><code>age</code></dt><dd>mother's age in years
</dd>
<dt><code>lwt</code></dt><dd>mother's weight in pounds at last menstrual period
</dd>
<dt><code>race</code></dt><dd>mother's race (<code>1</code> = white, <code>2</code> = black, <code>3</code> = other)
</dd>
<dt><code>smoke</code></dt><dd>smoking status during pregnancy
</dd>
<dt><code>ptl</code></dt><dd>number of previous premature labours
</dd>
<dt><code>ht</code></dt><dd>history of hypertension
</dd>
<dt><code>ui</code></dt><dd>presence of uterine irritability
</dd>
<dt><code>ftv</code></dt><dd>number of physician visits during the first trimester
</dd>
<dt><code>bwt</code></dt><dd>birth weight in grams
</dd></dl>
<h3>Source</h3>
<p>
Hosmer, D.W. and Lemeshow, S. (1989)
<EM>Applied Logistic Regression.</EM>
New York: Wiley
</p>
<h3>References</h3>
<p>
Venables, W. N. and Ripley, B. D. (2002)
<EM>Modern Applied Statistics with S.</EM> Fourth edition. Springer.
</p>
<h3>Examples</h3>
<pre>
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)
</pre>
<hr><div align="center">[Package <em>MASS</em> version 7.2-44 <a href="00Index.html">Index]</a></div>
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